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seLEKTUR

ELECTRONICSCONTENTS

March 1994Volume 20Number 220ISSN 0268/4519

In next month's issue

Headphone amplifierMains transmissionequipmentStroboscope lightDirect conversionreceivers - Part 2

Halogen light dimmerA lower frequencyreceiving systemFiguring it out-Part 15:Sine waves and othersand others for your

continued interest

Front coverThe PIC (ProgrammableIntegrated Controller) is a(fairly) new RISC -based(Reduced Instruction SetCoding) microcontrollermanufactured by MicrochipTechnology Inc. The articleon page 26 describes aprogrammer that enables alarge number of PIC16Cxand PIC17Cx devices to beloaded with your own

application programs.Software development forthese controllers will be thesubject of a short coursestarting in this magazinelater this year.

© 1994 Elektuur

ABCAUDIT BUREAU OF CIRO_ LAT/ONS

CONSUMER PRESS

I 4

15 PROJECT: 100 W high -end a.f. power amplifierDesign by T. Giesberts

10 NEW COURSE: 800535 hardware/assemblerSoftware by Dr. M. Ohsmann

26 PROJECT: PIC programmerDesign by M. Rose

50 PROJECT: Mini I/O card for the Casio FX850/880PDesign by M. Fanrich (hardware) andG.J. Klasens (software)

34 COURSE: Figuring it out-Part 14: Varying inputsBy Owen Bishop

56 PROJECT: Electronic fuseDesign by K. Walraven

62 Building electronic circuitsBy our design staff

60 PROJECT Car battery voltage monitorDesign by L Pipets

OMMIJNICATIONS

42 Direct conversion receivers - Part 1By Joseph J Carr, BSc, MSEE

52 DX TelevisionBy Keith Hamer and Garry Smith

PROJECT: AF signal tracerDesign by K. Feigl

Buyers' guide 74

Component ratings 67

Index of advertisers 74Letters 65

Readers' services 70-71Switchboard 67

Terms of Business 72

$

AF signal tracer - p. 5

100 W AF power amplifier - p. 15

PIC programmer - p. 26

N- 8Electronic fuse - p. 56

Elektor Electronics is published mo ithly, except in August, by Elektor Electronics (Publishing), P.O. Box 1414, Dorchester, Dorset DT2 8YH, England. The magazine isavailable from newsagents, bookshops, and electronics retail outlets, or on subscription at an annual (1994) post paid price of £27.00 in the United Kingdom; air speeded: £3400in Europe; £43.00 in Africa, the Middle East and South America; £4500 in Australia, New Zealand and the Far East; and $57.00 in the USA and Canada. Second Class Postagepaid at Rahway N.J. Postmaster: please send address corrections to Elektor Electronics, c/o Mercury Airfreight International Ltd Inc., 2323 Randolph Avenue, Avenel, NewJersey, N.J. 07001.

ELEKTOR ELECTRONICS MARCH 1994

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he tracer is based on the assumptionthat all that is required is knowing

whether the signal passes through theequipment or, if not, where it fails.

Rectangular or sinusoidalThe unit provides either a rectangular ora sinusoidal signal. The former is gener-ated by IC2 and the latter by T1 -T2. Selectionbetween the two is with S2b, while S2a se-lects an appropriate indicator LED. Theoutput level of the generator is set withP5. Transistor T3 provides a low output

AF SIGNALTRACERDesign by K. Feigl

In the design, fault-finding and repairing ofaudio equipment several pieces of test

instrument are either required or just down-right useful. One of these is a signal tracer asdescribed in this article. It consists of a signal

generator and a processor with which theinjected signal can be detected (and made

audible) at a number of locations in theequipment on test.

impedance. The test lead of the genera-tor is connected to K2.

The tracer/detector section is formedby IC3, whose input is via K3 and whoselevel is adjusted by P6. It is a straightfor-ward, standard application of an LM386.The test signal is made audible via a smallloudspeaker, LS1.

Power is derived from a 9-V mains adap-tor or battery. The supply line is stabi-lized by regulator ICI.

The sine wave generator consists oftransistors T1 and T2, which switch oneanother on and off in turn. Emitter re -

14

1C2

0 100n

min

IC2b5

7805'Clqq

sistors R4 and R8 ensure that this switch-ing is not abrupt and that the transistorsdo not become saturated. The result isthat the edges of the signal are not steepand that the tops of the signal are notchopped off: in other words, a waveformthat is very close to a sine wave.

The operating point of the generator isset with P1. The lower the output level,the better the waveshape. A good com-promise is an output level of about 30 mV(measured with a multimeter in positiona.c.). The distortion is then fairly modest.

The frequency of the generator, deter -

01

1N4001

C2 C1

10p 100n 100n 1000p10V 10V

NMI100n 100n

C15P6

C14

100kLOG.

S1

C16

TOOn

5V

.LF15

:100n

R14

C17

77n

940006-11

K1

BT1

9V

C18

1001J10V

LS1

852

250mW


Fig. 1. Circuit diagram of the a.f. signal tracer.

6 TEST & MEASUREMENT

+0Btl-0

Ls1

C2 C3

022

1.1

R2

R6

5

R3R4

R1

Fig. 2. Printed circuit board for the a.f. signal tracer.

A

Fig. 3. Completed printed circuit board.

mined by the values of R5, R6, C7 and C8,

is roughly 1 kHz.The rectangular -signal generator com-

prises four Schmitt trigger/inverter stagesand also produces a frequency of 1 kHz.The signal consists of short bursts about1 s lopng with a mark:space ratio of about50%. IC2d is the generator proper, whileIC2, sets the length of the signal bursts.Fine adjustment of the frequency is pro-vided by P2 and P3. The outputs of IC2a

and IC2d are combined by IC2, and in-

verted by IC2b. Preset P4 sets the level ofthe rectangular signal to about that of thesine wave, so that overdriving at switch -over is obviated. When S2 has been set asappropriate, the output level of the unitcan be set as required with P5. The sig-nal is then available at K2 via emitter fol-lower T3.

ConstructionThe tracer is best built on the printed cir-

AC1

C11

012

K3

0 0P4 P3 P2

C8 T2 C A B

0 0 0s2E D

C10

C6

1310 0 0 Ai

C7 09 01.0-0 n r:co

C150.011Ct

P6

cuit board in Fig. 2. Populating of theboard with reference to Fig. 2 and theparts list is straightforward. Figure 3shows a correctly completed board.

This type of instrument is, of course,best housed in an easily held small en-closure. Suggested front and rear panelfoils are shown in Fig. 6.

Two test leads are needed, and each ofthese may be made from two lengths (about30 cm = 12 in) of flexible, insulated cir-cuit wire, terminated at one end into testpins and at the other into a phono plug.

For most purposes, a battery supplyis fine. The unit draws a current of30-60 mA, provided that the volume con-trol is not set permanently to maximum(when the current exceeds 100 mA).

CalibrationPreset PI is intended for setting the level/dis-tortion of the sine wave generator. This isdone as follows: connect a multimeter(a.c. mV range) to K2, turn P5 to maxi-mum and set S2 to position sine wave.Adjust PI till the meter reads 30 mV. Ifan oscilloscope is available, adjust P1 forminimum distortion at a usable outputvoltage (25-35 mV).

Interconnect K2 and K3; switch S2 be-tween sine wave and rectangular waveand turn P4 until the two signals soundequally loud. The tone and length of theburst may be set to individual taste withP2 and P3 respectively.

Parts list

Resistors:RI, R2 = 180 SI

R3 = 1.2 k52

R4, R7, R8 = 1 kit


A.F. SIGNAL TRACER

R5, R6 = 1.5 kQR9 = 100 k52R10 = 1 MOR11 = 330 1c1R12 = 2.2R13 = 10 IcQ

R14 = 1052

Potentiometers:P1 = 250 Q presetP2 = 500 k4 presetP3 = 1 MQ presetP4 = 10 IcQ presetP5, P6 = 100 k52 log (16 mm dia)

Capacitors:C1 = 1000µF, 10 V (if mains adaptor is

used, rating must be 25 V)C2, C3, C5 -C9, C13 -C16 = 100 nFC4 = 101.1F, 10 V, radialC10 = 10 nFC11 = 1.51.1F, MKT (polytheraphtalate)C12 = 470 nFC17 = 47 nFC18 = 100 aF, 10 V, radial

Semiconductors:D1 = 1N4001D2 = LED, 3 mm, yellowD3 = LED, 3 mm, greenT1, T2, T3 = BC547

Integrated circuits:ICI = 4805 (7805 if mains adaptor is used)IC2 = 4093IC3 = LM386

Miscellaneous:Mains adaptor socket for board mount-

ing or (9-V) battery holder and clipK2, K3 = phono socket for board

mountingS1 = SPST switchS2 = double -pole change -over switchLS1 = loudspeaker, miniature, 852, 0.25WEnclosure, ESM 14/3 (available fromMaplin Electronics)

Fig. 4. General view of the a.f. signal tracer with top panel removed.

FaultfindingAlways start tracing a fault with an inspection of the outside of the equipment.Often, the fault lies in the mains cable or in the mains fuse.

On the inside of the unit, look for visible damage: burnt wiring, blackened re-sistors and leaking electrolytic capacitors quickly point to a likely source of thefailure. If nothing untoward is visible, check for short or open circuits, startingwith the power supply. With the aid of a multimeter, look for defect fuses, or a pos-sible short circuit of the collector -emitter junction of power transistors.

If these checks do not point to a likely fault, a signal trace should be carriedout. Switch on the equipment (it is assumed that the power supply is OK) and in-ject a signal from the tracer into one of the equipment inputs. Next, using thetracer, try to follow the signal from input to output. Where the signal fails to bedetected Is the source of the defect. If, for example, the signal is present at theinput of an operational amplifier or transistor and not at its output, the device isalmost certainly the culprit. It may still take some time (and cause a few headaches)before the ultimate reason for the defect is found.

+8,..12V

SIGNAL TRACER

POWER

SIGNAL TRACER

ED o oVOLUME

940006-F

Fig. 6. Suggested front and rear panel layouts for the a.f. signal tracer.



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74110574 164749C589 1.647440590 0.947440592 1.197440593 1.667440595 0.927460597 0987440620 1827440623 1527440633 182744C640 1.327440643 1.32

74407243 07674401244 0.5774407245 0.5274407251 ass74407253 0.51

74607257 a5474407258 07274401259 07874607273 0.6874401280 1987440728374407297 0,82

74914 0.4174F20 52874F27 0.2874F30 0.2874F32 0.2874937 0.41

74938 0.4474F40 0.6674F51 0.4474664 0.3274974 .

74F85 1.48

7400251 1607400253 ass7400258 ass7400273 1.107400283 1.40740029979097400373 0.947400374 0327400377 0.987400540 0.987400541 a987400573 1.38

78512 0.4878015 ass7905 0.287905A 0.327905FA 0.60

0.557912 0.307912A 0.367912FA 0.787915 0.3079187924

0.300.30

0.90/200V01L 0.383.010200v SIL 0.57609 00V OIL 1.6080/2000 SIL 1.96

35A/100V Sqr 2.98KBP01002 1.64KBPC3502 2.98W005- 1A/50V0.32W02G- 1.5A 0402W022KBB1OR/SIL 00:0.66

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Freq.= MHz1MHz £8.90 ea.

KM4402560Z-10 6.95M5M44649-15 4.60MK41164-54 2.8CMK45644-15 120NMC37644-15 1.6CUPD41464C-12 4.2CUPD414640-15 4.20UPD416C-2 3.4CUPD416C-3 360UP04460-1 2.6C

STATIC RAM

929709TEL 081-471

DIGITAL7440645 1.4074H0646 1.777460648 1.77

74407299 1.6474407354 1.2874407356 1.28

74988 0.41749109 0.58749112 0.72

7400574 1.387400646 P007400648 POA

791120 0.3579412A0P 0.3579M05 a42

2KBB20R/SIL 0.7068001500/50 a35B80C1500SIL 0 60

4,4.9152.6,8,9.8304,10,12,15,16,18.432. 19.5508,

2114-3L 3.4C4000 SERIES 4513B 1.20 4016BT 0.43 74160 0.94 74LS169 0.59 74L0669 1.07

4000B 0.16448511848B 11,1122 4400,178BBT7 00,7788 77441186310 01,2988 7744L1s0,17703 P00300 77441Ls0687780 p0.0768 7460651 1.47 74601365 a54 749113 1.30 79M05A 0.42 SKB6008/60A POA 20. 24. 25 5 313MHz

66,26644LpP-1102 22440C

400008 0 184001A 0.164001B 0 18

4516B 0.444517B 1.8445180 0.40

4020B7 ass402107 0.654023BT a38

74164 1.2074165 1.5774188

74101730 0.447445174 0.367415175 0.34

741_0674 17.6074LS682 26274LS683 PO0

74H0652 1.477440658 4.497460659 4.49

74407366 0.8074407367 as474907368 0.80

746114 1.3074E125 0.60749126 0.98

740 SERIES 79M05FA 0.6579M12 0.5079M120 0.60

CRYSTALSPrice: £3.521x.

30, 32. 31768,

62256LP-12 4.9562256LP-10 4.98CDM6116063 5.3074000 056

4001 U8 0.2240026 0.18

45198 0.3645208 a36

402401 0.76402507 0.38

74174 1.5374175 1.23

7445181 1.827415182 2.05

74LS684 3.8574LS685 POA

7440664 4097440665 4.49

74HC1373 0.4474607374 0.55

749132 ass74F138 0.5874F139 0.58

74002 ass74008 0.56

LM3177 0.50LM317MP 156LM317LZ 055

R041(RC18/U)

` rest MHz1543200 1.60

3133' 40 & 50MHzPrice: £4.45 ea.

CDM61170E3 580HM1-6116.5 4.3E

400613 039 45218 0.72 402781 0.45 74180 1,29 7415183 2.05 74LS686 P007440670 1.10 74401377 054 74010 0.56

2.000000 1.66 4513-6116-5 3.604007UB 0.20400813 0.4040090E 0.23

45228 0.8645268 0.5045270 0.56

402801 0.564029BT 0.864040E0 0.78

74184 POA74185 1.7674191 1.41

7415189 2.60741_0190 0.497415191 549

74L0687 POA74LS688 1.987415693 POA

7440677 3787490678 5.917460680 3.83

74401390 0.6874401393 08874607394 am

749148 D.94749151 D.58

749153 D.62

74014 0.5674C20 0.9874030 0.98

1_M338K 4.45UA7EIGUIC 1.02U07901.110 1.02

1.49' ''''3276800 0.983 1.10

ProgrammableCrystal

Oscillators

HM6116LP-2 2.6C5616116LP-3 2601-1M6117LP-3 5.70

4009UB 029 45288 0.49 404287 0.74 74192 1.41 74L0192 0.49 741_0794 POA7490682 4.21 74401423 162 749157 D.58 74032 0.68 R041954 150 579545

3.686400 1.02 HM62256LP-10 73340108 0294011B 0.18

45298 0.57 404601 1 41 74193 1.65 74L0193 0.48 74LS795 POA7490684 5.7074110688 0.87

74607533 1.4474407534 0.75

749158 0.70749160 1.10

74042 18874048 298

DIODES 4.000000 1.02 -EXO 3C SERIESElpin DIL Plastic

HM6264ALP-12 330HM6260ASP-20 198

4011U5 0.1845308 1.9245315 1.14

404781 1.06404961 1.06

74221 1.2374259 232

741_0194 05474LS194A 0.57

74LS796 POA74L0797 POA

7490690 1.62 74407540 0.64 74F160A 1.10 74C73 1.28 142986RB 18.204.096000 1.104.194304 1.10

Package HM6267P-35 55740120E 11640128 0.204013B 0.20

45326 0.4445348 2.8245368 1.22

405081 008405107 078405281 184

74265 1.4674273 POA74278 3.56

74151950 0.5774LS196 0.6874LS197 058

7415848 POA7440691 1.627490692 1.737440693 1.73

74407541 0.6474407563 0.9874607564 0.78

749161 1.10749162 1.28749163 1.28

74074 09474C76 1.2674085 186

143881 2.541539970 6.55154001 0.04

4.433519 1 10

4.608000 1.104.915200 110

9'99 - Mhz12. 14.31818. 16,16.384,19.8808 &

HM628128LP-8018.50

HM66204L-12 15.8074HC SERIES

40148 0.42 45380 0.60 405307 0.98 74279 1.38 74LS221 144 746000 0.19 7490696 1.48 74407573 as4 749164 1.28 74090 1.29 154002 5.000000/6 15220MHz KM62256ALP-10 4.95

40158 0.42 45396 0.82 406007 0.84 74283 1.26 7415224 20.24 746002 0.19 7460697 1.24 74601574 064 749166 4.3248

74093 2.10 1 44003 5 068800 1.10Price: 63.92 e4' 1451640-101 2.40

40168 0.244017B 0 38

4541E1 0.5245438 057

406607 0.59406861 0.38

74298 POA74365 0.70

7410240 D.427445241 0.42

744003 0.24749004 0.19

7440698 1.247440699 1 24

74401583 0.0074607597 1.52

749168 4

74F169 3.5074095 150740150 5.40

144005 0.04144007

5 242880 1.205.888200 1.80

16pin DIL PlasticP2114AL-2 140P2114AL-4 140

4018B 0.38 45446 2.11 4069067 0.38 74387 1.06 7415242 0.42 7450004 0.24 74404002 035 74401640 134 749174 0.78 740151 3.94 154148 0.03 6000000 1.02 996'9" P0D5101P 3.3040198 0.26 4547B 1.68 407013T 0.38 74393 204 74LS243 0.42 745C05 0.20 74404015 1.07 74HC7643 134 749175 0.76 740154 5.82 1N4149 0.06 6.144000 1.02 PmFrarable for UPD43256AGU101_4020AE 0 36 45498 POA 407101 0.38 74403 POA 740244 0.42 749008 0.20 74904016 0.44 74407645 1.11 749181 4.48 740157 3.80 194150 0.08 0400000 1.84 57 00f- Frequency 8.33402013 0.38 45518 1.82 4075E0 0.38 74423 POA 74LS245 0.42 745010 0.29 74904017 0.42 74407646 2.40 749182 1.80 740164 254 1N4446 0.06 6.552000 1.40 UPD432560-12 5.6040218 0.40402213 0.40

45530 2.3745546 6.01

4077E0 0.384078BT 0.38

741_0247 0.4474L5248 0.6B

745011 0.20746014 0.25

74604020 0.5274404022 0.56

74407648 1.9074907651 1.64

749189 4.98749190 3.40

740185 2.54740221

154728A 0 24-

1447350 0.246.553 1 21600

7.372800 0.78

SPG8540AN0.005 to 600kHz

UPD4360C-15 4.70

74L5 SERIES40238 010 45558 0.48 408191 018 7450140 0.34 74404024 0.50 74407652 0.00 749191 3.20 740240 1547360 024 8.000000 1.00 UVPROMS4023UB 023 45568 0.49 409387 0A5 741_000 0.18 7410251 0.32 748020 0.22 74604028 0.58 74407670 1.10 749192 3.20 740244 2.08 1N4740A 0.24 8.867230 1.34

SPG8540BN

40240E 0.27 4557B 1.88 409481 0.95 74LSO1 0.18 74L0253 0.44 745C21 0.22 74404040 0.50 74407673 1.64 749193 3.20 740373 2.08 1647430 0.24 9.830400 1.20 9.0993 t01MHz 270128-25 3.9840248 0.32 4558B 2.18 450897 255 74LSO2 0.18 7415256 0.78 7411027 0.22 74604046 1.54 74607688 1.10 749194 740374 2.08 1N4744A 0.24 10.00000 1.10 270640-15 3.984025B 0.194026B 0.54

45606 1.5145618 1.74

4510131 1.354511BT 1.35

741_503 0.18741_504 0.21

7410257 0.3474LS257A 0.46

746030 0.22745032 0.22

74604049 0.4874604050 ass

744074002 0.39749074015 1.13

74F195 2.24749219 4.38

74C901 1.18740902 1 18

1447560 0.241N52268 0.09

10.69500 1.90sp- Ga44°CN0.064 to 78810-8

270256-15 3.98270256-25 3.90

40270 0.30 4562B 5.15 451287 0.68 74LSD5 0.21 74LS258 0.44 74H042 0.48 74604051 164 744014016 0.52 749224 POA 740903 1.52 1452329 0.09 12.0 0.92 027256 5.404028B 0.38 45669 1.10 451487 2.20 741506 0.51 74LS258A 0.48 74H051 0.29 74404052 0.68 744014017 ass 74F240 0.62 740906 1.10 1452349 0.09 13.87500 2.40

SPG8650BN 2705120-12 6.4640290 0.35 45685 5.17 451687 1.02 74LSO7 051 741_5259 0.48 745058 0.42 74404053 0.68 749074020 0.74 74F241 0.62 740907 1.10 145337E1 0.48 14.00000 1.64

0.00083 to 100kHz 27010000-12 8.9240308 0.21 4569B 3.04 4518B7 Y18 741508 0.18 7410260 0.22 745073 0.34 7440405301.10 744074024 ass 746244 0.62 740908 2.20 145349B 0.48 14.31818/S 0.85 2704096-12 POF,40318 1.04 4572UB 0.70 452OBT 1.18 741509 0.18 7410266 746074 0.25 741104060 0.47 744074040 0.70 749245 0.72 740911 14.42 1"3, n2, 0.48 14.74560/5 1.10

, 9.2,HM270101G-20 9.80

40328 0.70 4573P POA 452187 1.07 74L510 0.18 7440273 0.42 741-1C75 0.40 74604061 2.52 746014046 210 749251 0.62 740912 14.42 1453576 0.48 14 74580 1 10DC to DC H42701024HG10

40338 0,58 458013 B.84 452287 1.22 74LS11 0.18 7410275 POA 746075 0.40 74904066 0.467440406600 54

746014051 0.96744014052 0.96

74F251A 0.6674F253 0.62

740914 1.16740915 2 74

1453658 0.48 15:00000/5 1.10 ."'"verters 156340340 1.1040356 0.39

45818 3.854582B 3.85

452867 0.884534BD POA

741512 0.18741013 0.19

7415279 0.337440280 0.86

74H077 0.51746C85 0.48 74604067 4.72 746014053 084 749257 0.62 740922 6.80

1653668 0.48111537081 0.48

16 00000 1 0216.00000/5 120.

TDK CE -0344 56044270649P -20T 1404427064G-15 4.2C

40368 2.57 45838 0.86 453807 1.05 741814 0.24 7410283 0.45 746086 0.28 74904072 04574404075 0.32

744014059 2.24744074060 0.84

74F257A 0,66749258 0.62

740923 6.80740925 930

1115380B 0.48 18.43200/6 1.10 3W5R 15-15 27:50 4427064G-20 4.204037B 1.274038B 0.7840386

45840 0.570.49

4541E0 1.05454307 1.02

741515 0.36741520 0.18

7410290 0.487410292 16.85

74HC93 0.447440107 0.39 74404078 0.46 746014066 0.66 74F259 POA 740926 910

145401 0.11145402 0.11

19.66080/5 1.2020.00000/5

11'860

IPL S.010 23.40 44462532P 4,084448271280-25 4.58

40398 3.22 4597CP 6.90 4555BT POA 741021 0.18 7410293 0.38 7440109 0.35 74404094 064 74H014067 4.93 74F260 0.78 740929 9.30 146287A 1.55 2211840/S 1 Watt DC/DC 56482764G asc404013 0.42 45988 6.90 455601 1.05 741522 0.18 7415294 17.82 7460112 0.40 74404316 058 7419074075 0.36 746289 7.48 74S SERIES 1 N825 1.80 24.00000/S 1:882

5V input 01351put M2716-191 15040418 0.41 45998 5.50 458587 0.95 741524 0.58 7445295 1.11 7490113 0.40 74904351 189 749014094 0.84 746273 0.84

1N825A 1. 27.64800/S 1.20DIL 8 SIL by M5L2732K 4.4C

74000 0.444041UB 0.32 47200 POA 4010687 053 741525 0,18 741_5295A 1.15 7480123 040 74604511 0.55 749014316 0.68 749280 ass19827 I 30.00000/5 6.9 Newport M51_2764K 130404213 0.323247200 P00 4024497 1.35 741527 0.18 7415298 0.98 7450125 as° 74904514 118 741-1014351 1.04 74F283 0.92 74502 a44 105252900000/5 1.40

NMA0505z5V MBM27064-20/2104043B 0,38 47238 POA 4037391 234 74L828 0.24 74L0299 183 74501213 0.47 74604515 1.42 744074510 154 74F299 POA 74503 ob.,

5082-2800 0.66 48.000000 1.68NMA0509E9V 4.9C

40446 0.36 47248 1 90 741030 0,18 74L0321 3.82 7450131 0.52 74604518 050 744074511 0.94 74F323 POA 74504 0.42 50822810 1.40 s . &des NMA0512E12V MBM270128-30 4.2C40456 0.94 4731VP ass 74 SERIES 741531 1.58 7413322 POA 7450132 0.32 74404520 0.72 749074510 1.64 74F350 1.50 74508 0.42 5082-2835 0.44 NMA0515.1.15V MBM27C258-30 5.104046B 0.42 4737VP 18.28 741_032 0.20 74L33220 POA 7450133 0.32 74604534 0.00 744074515 2.50 74F352 0.64 74509 6 AA119 0.60 11033/0 P1i8e:07.9000. NM027C2560-2540478 018 4738VP 1850 7400 0.36 741533 0.20 7413323 3.24 7450137 0.76 74604538 0.68 749074516 181 74F353 1.14 74s, 0.98 00144 0.72 4.90404813 052 4750VD 28.50 7401 0.30 741537 0.18 7415347 2.86 7450138 034 74604543 0.81 749074520 0.90 746365 1.28 74511 48 00215 0.58 0.204800 8.23 DC/DC Converters N610270640-25 3.6840498 0.24 4752VP 29.25 7402 0.34 74038 0.18 7410348 1.98 7450139 0.31 74607001 1.01 744074538 1.02 74F366 130 74032 0.48 0.58 0.307200 899 by Computer TMS2516JL-45 4.52404908 018 4753VP P00 7403 0.34 741040 0.18 7415352 1.68 7450141 0.61 74407002 1.01 744077007 0.39 746367 1.48 74022 0.78 AAZ18 0.48 1.000000 195 Products TMS27128JL-25 4.6040505 022 4754VP POA 7404 74LS42 0.32 7415353 1.88 74140147 0.61 74407032 1.01 744017046 180 74F368 1.30 74040 0,25 BAV10 0.08 1.843200 3.71 PM623 2460 10102716k-45 4.60405113 034 40085 1.98 7405 0. 741044 2.11 7445363 2.10 74110148 055 74607266 a84 7440740102 2.43 74F373 0.62 74551 036 8AV45 498 2.000000 065 PM671 2610 0P0272560/210 5.60405213 0.33 40097 0.62 7408 74L047 0.55 74L0364 POA 74110151 0.40 74607074 1.99 7490140103 1.48 74F374 0.82 74564 0 3 BAW62 2097152 171 PM672 2,70 UPD27320/21V 09040535 0.34 40098 0.62 7406A 0.72 74048 0.54 74LS365 0.30 7450153 aso 74407292 1.10 7440740104 2.71 746377 0.92 74574 0.98 804/16 0.06 2.457800 1.92 PM903 44:00 0P0270256D-15 5.8040545 0.68 40100 2.48 7407 0.63 741549 1,38 741_0365A 0.34 7450154 0.98 74407294 1.10 7460740105 1.82 749378 1.58 7088 1.12 BB204 0.32 2.500000 1.92 PM951 46:00 UPD27C512D-15 6364055B 0.62 40101 POA 7407A 0.85 74051 0.19 741_0366 0.36 7450155 0.69 744040102 1.10

74HC SERIES749381 3.88 745112 1.08 05212 2.48 3.000000 225 RESISTORS UPD27064G25 4.90

405613 0,48 40102 1.20 7408 0.37 741554 0.19 74L03660 0.42 7480157 0.42 744040103 1.10SURFACE 746355 POA 745124 2.42 131340513 0.22

40598 2,98 40103 0.88 7409 0. 741555 0.32 741_0367 0.29 7450158 0.47 749040105 1.40MOUNT

749395 POA 740132 0.98 85809 0.60HC49/U4H

METAL FILM EEPROMS4060B 0.38 40105 1.82 7410 0. 741573 0.40 741_0367A 0.34 74501130 164 74F399 0.98 740133 0.73 81179 0.42 a25w 1%74HCT SERIES4063B 0.42406613 0.27000040105 0.30

40107 0.4274127413

74073A 0.4874074 0.22

741_0368 0.3674LS368A 1.72

7450161 0.427450162 a64

744COOM 0.32744002M a32

749412 POA74F413 POA

740134 1.9524s,, 81260.200 3.58B7261-200 3.88

3.275800 16 6

3.579595 1.58 E24 Series100 to 1M 3p each

28064-25 38028054-15 10.907440700 a227460702 0.220.32.

7440703 a26

406713 1.85406813 0.204069UB 0.21

40108 P0840109 1.2440110 1.04

7414 7274187417 0.

7415740 0.24741075 0.28741076 0.68

7415373 0.387415374 0.447415375 0.42

74E10183 a4274110164 0.4274110165 0.55

74HCO3M 03274HC04M7440204 0.32

74F432 P0874F521 1 20746524 P08

745139 0.740140 78249152 1.26

BYV28-100 0.99B1032.50 180008805 0.80

5'09225

86 20 1497 ' A'8.000000 1.14

N.B Min Qty. OrderMin. 5 c280256-15P s per value

280256-20 25.8927.50

280256-1500 213.5C4070B 0.214071B 0.2040728 0.20

40114 2.6240116 12.4840117 1.80

7420 0.3774257426

741076A 0.7279LS77 0.4274078 0.32

7410377 0.687410378 0.987415379 0.99

7450166 0.887450173 0.767460174 0.42

7460704 0.227440708 a227460710 0.22

744008M 0.32744C10M 012744014M 0 36.

74F533 1.20749534 1.20

.749537 1 60

749157 1/2749163 2.80740174 092

DS16C 0.40MV1404 15.90MV209 120

10.00000 2.2511.05920 24012.00000 1.1414.00000 2.25

METAL FILMPRECISION

0.25 WATT 0.1%

X281600 5.10X2816AP-25 010X2864AP-35 12.20

40735 0-2040758 "9

40147 1.23401130 0.54

7427 597430 0.3574083A

741583 0.390.39

7410381A 4.96741_3985 3.48

7450175 0367460181 1.84

7440711 a227460114 0.267450120 0.26

746020M 0.36745030M 0.36745032M 0 36

74F538 1.6074F539 1.80741540 1,98740189

740175 1.35740182 3.28

0A200 01000202 am 16 00000 1.14

20 00000 1.52

Series240019se100R to 255K

24001 1.6224002 1104076B 0.42.

4077E1 0.2040161 0,5440162 0.54

74327437 0.59

744585 0.38741_086 0.27

7415386 0.9111

74LS390 0.46

7450182 0597450190 0.87 7440721 0.26

.

7440740 0.36 74F541 1.913214

745195 2.400047 0 140090 0.14 24' 00000

.i s, Price: £0.94 each 240042.9E24018 540

4078B 0.21 40163 0.54 7438 0.49 74L090 040 74LS393 0.40 7490191 0.52 7460127 026 74HC75M 0.34 749543 3.98 740240 100 P645368 ass ups -I HIGH PRECISION 280040-20 4.4040818 0.1874024140174 0,34 7440 0.77 74L091 POA 74LS395 0.66 7440192 077 74110730 0.26 74HC85WM 0.65 74F544 P001.12 P640470, 0.55 NON -INDUCTIVE 59011 144

4082B 0.20 40175 0,47 7442 0.55 744.392 P00 74LS3950 0.94 7450193 054 7450102 0.22 74HC86M 136 749545 POA 740244 1.77 8EC53A 040 8. 225 WIRE WOUND 93006 1.12

40800 0-38 40181 P08 74451.20 741593 0.44 7415396 P08 74110194 0.67 7450742 0.46 7440123AM 0.46 74F547 POA 740257 1.22 ZPD2.7V 0.06 8.192000 252 0.15 WATT 0.1% 93046 1.2840868 0.38 40192 0,62 1.53 741095 0.48 74L0398 POA 7440195 7490773 036 7440125M 146 749573 2.92 740258 1.22 10.00000 22540898 0.98 40193 0.74 7447 0.98 74096 0.82 74L5399 0.81 7450221 044 7460774 0 26 7440132M 0.42 749574 2.92 745260 0.70 ZENER DIODES 11.00000 225 Temp.Coett.3ppm MISC. MEMORIES4093B 0.24 40194 1,82 7447A 1.87 741_0107 0.28 7410423 0.98 74110237 0.73 7440175 0.36 7440138M 0.38

7440139M a38749579 7.96 740273 2.44 MISC. 12 28800 2.66 10R,50R,100R250R,

40948 038 40195 2.24 7451 0.57 74LS1070 0.38 74L5445 POA 74110238 0.64 7460185 0.60 749804 4.84 74274 2.42 15.00000 2.25 10K 1006 6341-1J 4.58409513 0.70 40240 2.62 7454 0.72 74LS109 0.28 7410450 10.68 7450240 0.44 7440186 0.36 74HC154WM 0.64 749620 POA 749280 0.96 BZY93C7V5 2.66 17.73497

22.8500

Price:'E3.85 each AM2145-4500 5.444096B 1.10 40244 1.36 7470 74LS1090 0.32 7410481A 7.16 7490241 0.44 7440793 0 58 7440157M 538 749621 POA 740283 1.90 BZY93015 2136 18.00000 0M270281PC 3.9E40978 2,75 40245 1.36 7472 38 7415112 0.28 7445465 3.82 7440242 0.80 74907107 0.40 7440161M 0.48 746623 POA 740374 2.18 8ZY93018R 2.66 20.00000 2.25 HIGH PRECISION 1017130LA-100P4098B 040 40257 0.54 7473 59 74L51120 0.34 7410467 7.78 741-1C243 0.88 74407109 0.42 749C164M 0.48 749646 515 740394 2.10 BZY93020 266 21.00000 2.25 NON -INDUCTIVE POA40990 042 40373 1.10 7474 0.53 74LS113 0.32 74LS468 7.78 7450244 0.43 74407112 0.42 7440165M 157 749676 POA 740412 270 BZY93024V 2.66 24 00000 2 80 WIRE WOUND 10171324A -100P4104P 1.01 40374 1.10 7475 0.67 741,01130 0.38 74LS469 8.10 7490245 0.44 74407123 0.64 7440173M 0A8 749821 3.98 740436 2.62 620930338 2.66 0.33 WATT 0.1% POA41608 0.85 45026 4,42 7476 0.72 74LS114 0.32 74LS469A 6.70 7440251 0.35 741107125 0.56 7460174M 0.38 74F823 P00 745437 282 B2T030120 0.40 CRYSTALS MISC. MB8414E 4.9041618 0.85 45027 5.99 7480 1.26 741_0114A 0.36 74LS490 2.85 7440253 0.52 74407126 056 744C221AM 0.65 746825 POA 740472 232 BZX610902 0.09 Temp.Coeff.3ppm MCM40278C3 28041748 1.27 45028 4,49 7483 1.10 74LS122 0.39 74LS491A 12.82 7440257 0.47 74407132 0.50 74HC240WM 0.55 746827 745734 252 BZX610240 0.09 6043/T 19,5R.10R,20R5OR N82012804 2.4041750 1.14 45040 POA 7485 0.58 741_0123 0.36 741_0502 POA 7440258 0.73 74401137 0.52 74HC244WM 0.55 746841 4.48 ZENER DIODES 1.000000 599 price: £0:60 each 9825153N 5.80VOLTAGE

REGULATORS41940 1.43 45041 POA 7486 0.53 74LS125 0.28 74LS540 0.80 7490259 0.65 74401138 032 744C245AW as2 749843 4.93 400mW N82S181AN 6 OS

'44099 11.05 45100 POA 7490 0.76 74LS125A 0.32 7415541 0.80 7440266 0.36 74901139 0.45 7440251M 0.42 749845 POA 2.4V to 75V MINI CYLINDER 1008,1201, 2508 NM06504.1-9 3.40

78008AP 1.1544106 16.45 45106 7.98 7490A 1.34 741_5126 0.32 740569 P00 7440273 154 74607147 0.68

74601151 0 527460259M ass741-10273WM ass

7491244 3.75 Price' 6p each 0.032788 088 '

500R,1 K, 24, 5K, NMC93066 1.454411P 21.5844129P P00441291_ POA

45109 POA45138 POA45145 10.04

7491 2.567492 0.6774920

741_0126A 0.3674LS132 0.29741_0133 0.18

7410573 1.347410574 1.347415590 4.85

7490279 0.517440280 0.897440283 0.58

74607153 0.4474401154 1 24

741-1C367WM 0.53744C373WM ass

7400 SERIES 7805 0.2878050 a32 ZENER DIODES

500mW

WATCH0.032768 582

10K 20K

Price: 0.15 ...hP5101L-1 3.9CTBP180030N 1.74TBP24S104 190740000 0.38

740002 0.49MEMORIES441 2VP POA 45146 POA 7493 741_0136 0.38 7415592 5.28 7490298 173 74401157 0.44 741-10374WM ass 780590 0.45

2.4V to 200V CRYSTAL 709240010N 3.1144166 P00 45151 19.50 7493A .70 7410137 0.98 740593 5.79 7440299 1.06 74401158 0.48 74HC390M as7 7806 528

ice: 6p each'

OSC. MODULES TC5501P 3.50DYNAMIC RAM4419P POA 45152 21.45 7495A . 741.0138 0.31 7410595 4.85 7490323 1.58 74601160 056 74HC393M 053 740004 0.40 7808 018

TC5504AP-2 3.40

"In OIL4429PB POA 45156 15.80 7497 5.23 7415 t39 0.34 7410597 4.95 7460354 0.55 741-1C1161 0.56 74HC540WM a76 740008 0.40 7809 a32ZENER DIODES 7C5516PL-15 4.20

4433P POA 45157 14.38 74104 0.67 7410145 0.66 7415621 P00 7440356 0.65 74607162 0.84 74HC541WM a76 740010 0.40740011

7812 a281.3 WATT

Plastic pkg 4164-10 1.40 705517AP-2 4.204443P POA 45158 11.94 74107 160 74LS147 2.88 7410622 P00 7490365 0.41 74601163 056 74HC573WM 1.09 0.40 78120 012

2 7V to 200VTTL Output 416012 1 20 105565PL-15 3.60

4447P POA4468P POA

45159 POA45406 2.73

74110 POA74116 3.10

74L0148 0.83741_0151 0.32

740623 2.987410624 2.10

7440366 0.527440367 0.97

74607164 0.5274601165 0.52

74HC574WM 0.84744C688WM 0.84

740014 0.40740020 0.40

7812070 0.327815 0.28 Price:10p each

4 Pins spaced atcorners of 8pinDIL

4164-15 12041255-8 240

T MS0014.101_ 3.40

4469P P00 45407 6.47 74118 POA 7440153 0.32 74LS625 5.37 7440368 0.52 74401166 0 52 74604017M 0.48 740032 0.40 7818 0.28ZENER DIODES

41256-10 200CAPACITORS4489P POA 45411 POA 74119 P00 7410154 1.12 74LS626 P00 7440373 0.44 74401173 0.52 74HC4020M 0.48 740074 048 7824 028

3.0 WATTme 41256-12 2A0

4490P 3.20 45414 15.60 74121 0.98 74LS155 0.34 74LS627 P00 7440374 0.44 74407174 0.52 74H04040M 0.44 7400109 0.64 78L05 0.247.5V to 270V

4, 4.9152, 8, 10, 41264-15 224 SURFACE MOUNT4495P 527 45428 POA 74123 0.94 741E0156 0.38 7410628 1.78 7490375 0.76 74601175 0 52 74404046M 1.68 7400112 0.81 781050 0.28

Price12, 15 8 20 41464-12 4.45

4497P 11584499P 624

45433 POA45440 POA

74125 0.6774126 0.98

74LS157 0.387410158 034

74LS629 1.9874L0631 POA

7440377 0.517440386 0.29

744071E11 3.2474601182 0.96

74404060M 0.4874HC4066W 0.84

7400138 0557400139 055

78L05ACLP 0.4078L050CZ 028

40 eachZENER DIODES

Price:22.ss ea. 41464-10 4A54464-10 2.80

Multilayer Ceramic63 VOLT

45008 19.4545016 0.32

45025 "845441 POA 74128 1.19

74132 0.8674145 1.16

74LS160 04874LS1600 0.547415161 146

74LS639 PO074LS640 03874L5641

7440390 a3874H0393 0.4174H0423 0.64

74407190 0.6474407191 0 6474601192 0.94

74404538M 0.78 7400151 0.687400153 0.657400157 0.81

7E11E12 0.28781120 0.2878L12A0Z 130

5.0 WATT3.30 to 200VPrice:42p each

24. 32, 40 850MHzPrice 83.40 ea.

4142568-70 3.9044025692-10 8.85440256-8 5.00

Case Size 1206L211W1.2514.16'74F SERIES

4" SERIESSURFACE 74900 0.2845038 0.38 74150 1.86 74151610 0.49

0387415641-1 118 7490521 0.95 74407193 0.64 7400158 0.65

74001637E115 0.28

ZENER DIODES511000-85 805 10092209 3309

47pF4504B 1.12 MOUNT 74151 0.80 741_0162 0.48 7410642 0.98 7440533 0.95 74401194 1.13 528 050 78L24 528 8pin DIL HM484113AP-15

100pF 220pF 330094505B 042 400107 a32 741518 0.80 74L01620 1.07 7410642-1 POA 74110534 089 74501195 1.16 24,4 0.28

7400169 1.98 78L56 1.10 STUD MOUNT20 WATT

sem, Metal 450 470p9 100059 2200pf4506B 1.14 400281 0.32 74153 0.90 741_0163 0.42 74LS643 POA 7490540 ass 74401221 0.98 24,6 074

7400174 0.65 78M05 a327.5V

Package HM48415AP-20425 3300pF 4700pF45060 1.14 401101 0.32 74154 2.16 741S163A 0.47 74LS644 POA 7440541 0.60 74401237 0.94 74F07 0.74

7400175 050 78M05A 0.36 to 75V

Pk,HCMOS Output HY53C2564.5-80 10000,

45080 1.14 401101310.32 74155 0.81 741_5164 0.34 741_0645 1.12 7440563 ass 74401238 0.51 74,8 0.287400191 118 78M12 012 £4.84 ea. 150 22000p9 33000p9

45105 0.54451113 0.44

401207 032401381 0.4574158

74157 0.74 7415165 0.59 74L5645-1 1.28 7490564 ass7440573 0.64

74607240 0.5574407241 0.55

74910 0.2874,1 028

7400240 0.927400241 032

78M12A 0.3678M130 0.65 BRIDGE

13.2mm sq.Pins spaced 41

H75304641S-80395

Price'. 150 each

45128 0.38 401507 0.841.57

74159 3.9874LS166 5597415168 575

741_0646 5.857415652 POA 74405730 an 74601242 0.76 74912 as2

7400244 0.927400245 1.10

78M15 03278005 0.48

RECTIFIERS corners of 8pinDIL 906511000-85 8.45 4700009 100000pFPrice: 18p each


Please mention ELEKTOR ELECTRONICS when contacting advertisers 9LM340T5 0.30 NE536H 4.90 TL071CP 0.64

MICROPROCESSOR& SUPPORT ICs

HD1-0165-5 10.9690146818AP 4208D3-6402-9 6.16H03-6440-9 8.89HD3-6495-9 8.89HD44883 9.52H046505SP 9.85H046802P 5.50HD6321P 4.20HD63485PS32 3250HD63B03XP 11.958068000-8 11.59H06845SP 6.92HD68A52P 5.60HD68821P 4.29H13-7159.5 20.98H13 -7159A-5 23.40HM10422 14.302820864 17.06136402818E 10.20M6402IPL 7.75

SAB8155-P 382 TIL100SAB8259AP 3.59 TIL111SA682054-2.P 412 TIL113SAB82C55A-2-P 4.80 TIL117SC80C4514on6413.60 TIL1SCN2661bc1428 3.35 TIL311SC N266100428 3.35 TLP504APALI 6R4-15CN 2.98 TLP5214GBTL16C552FN 1258 TORX173TMP7002NL-2 4.97 TOTX173TMP8085AP-2 5.98

1.980.600.60

19

1.584.204964.96

CL7611DCPA 1.32CL7621DCPA 1.98

0L7622 POACL7650CPD 4.98CL765OSCPD 627CL7652BCPD 8.24CL7652CPD 8.24CL7660CPA 1.40

CL766OSCPA 3.80CL7662CPA 440CL76638CJA 6.78CL7663BCPA 5.10CL7664CPA 7.95CL7665ACPA 4.98CL7673CPA 1.38CL8052ACPD 8.73CL8068AJD 11.38

3.75CL8069DCS0 2E8CL8069DCZR 2.88

L8211CPA 256

LM343H 8.80LM346N 3.96LM348DP 0.40LM3489 0.40LM350T 6.85LM351N 2.60LM3589 0.32LM359N 4E8LM360H 7.72LM361M/SMD 6.40LM3631-4-100 1650LM369DN 3.52LM369DRC 3.70LM3809 1.20

LM381AN 7.88LM385Z-1.2 2.20LM385Z-2.5 2 20LM386M-1/SMD 1.65LM3869 -I 1.40LM38651.3 1.80LM386N-4 2.60

NE5530N 3.82NE5532AN 1.58

NE5532N a80NE5534AN 1.80NE555N 0.20NE556/SMD 0.70NE556N 0.38NE5589 2.28NE564N 142NE565N 2.94NE567N 0.65NE568N POANE570N 4.60NE571N 140NE589N 425NE592/SMD 1 80NE5929 140NE592N14 0.92NE602AN 2.98NE6029 2 40

TL072ACP 1 48

TL07209 050TL072CP 0.50TL074ACN 2.85TL074CN 0.84TL081 CP 0.48TL082CP 0.49TL084CN 0.48TL27L2CD/SMD 1.98TL497ACN 3.44TL507CP 4.03TL7702ACP 2.04TL7705ACP 2.04747705CP 2.04TL7709ACPTL7770-SC 3.82TL783CKC 5.10TLC2201CP 3.74TLC2274CN 2.85TLC25I CP 2.54TLC2652CP 4.92

manamm75107 1a275107A 1.0275108 1.80751,A 18475108B 208751098 2.4675110A 1,3675113 30275114 3.0475115 1.6078118 3.3075121 2.6078122 ROA75136 3.10

4402.65

75150 I 60751508/ 2.65

75152751

6.36

1.75

BC182 008BC182A 0086C1828 0.08BC182L 0.06BC182L8 0.08130183 008801830 008BC183L 0.08BC184 0.0800184/3 0088C184L 0.08BC184LC 008BC212-18 0.08BC212A 0.08802126 0.0800212E 006BC212LB 0.08130213 0.08BC213L 0.08BC214BC214L

0.080.11

BFW10 1.20BFX48 0.49BFX85 0598E088 a30BFX89 1.598E050 0.34BF752 034BFY90 0.9280107 0.2860170 03890250 0.52BSR60 0 48BSX20 0.38BSX21 0.48155X61 1.85

13T136-600 110BUW46 4.9460211 180811211A 1.62

BUZ47AIRFZ14

E901.14

1001140EC 7.401003XP0141DC 9'8.76

80636321P 420

9563485CP32/Sm 1963803X8 10.076502 3.986502A 5.4065208 4.406522 4406522A 5266551 4 436551A 4-436500282 5.84-

65002P3 ,065C102P2 7006502282 4.80

65051E-1 3 8065051E-2 ,I'38

TMS3477NL 8TMS3700NSB 8.78TMS3702ANS 8.78 3630BM/BBTMS3835ANS 7.55 49620/BB

555TMS77C01NL 10.74751386341-1JTMS9900NL 24.4075140741-OPAMPTM59901NL 14.16CL8069CCS0

TMS9902ANL 15 94 ADOPO7CNTMS9914ANL 23.10 8252011'TMS9928ANL 740 AD524

LINEAR & MISCS .68

3.40POA

-TIMER 0.20

P080.18214POA

21.52

AD554JH POA68000P-10 898 M6403IPL 10.80 TMS9995JDL 6085

AD537,H POACL8212CPA 248

LM387A5NE604AN 8.24

TLC2654CP 4.847515,ki 1 75 80237 0.08 IRFZ20 1.77

680008-16 1820-MS2600P.15 440 UA96368CP 1.98

A0548J9 1.80CM7170IPG 842 5.90 NE6059 8.60 75155 120 02239 0.12 /113 0.39

680008-8 6.5068008P-8 785

NS82504 7.80NS6250N-B 7.80

UA9637A 198UA9638CP 198 AD578JN POA

A0581JH 8.92

M7207AIPD 642M7207IPD 6 42

LM3889-1 425LM3899 3.40

NE612AN 2.87NJM455613 1.20

TLC271CP 0.84TLC272CP 1.30

75157 4.4075159 545

BC307 0a800327 0.08

J175 0.68J270 092

68010P-12 POAM5M82C51AP 420M5M82C54P-6 5.40

UA9639CP 1.98UM684513 4.95751808AD581KCSA/SM09.97M72091P8 3.75

CM7211AMIPL 4.68LM3900N 1 60LM3909N 2.64

NJM4558DX 1.20OPO7CJ 3.60

TLC274CN 2.40TLC339CN 1.98

5.98

75161A 64713G328 ape80337 0.08

JA101 0.48MBD501 1.10

6802P 3.40MA880318H1 2P 4.56 0M9151 p04 A0585A0 POA M7211MIPL 4E8 LM3914N 440 0PO7CN 095 TLC372CP 1.40 751828 7.5g BC337-25 0.08 MJE13070 1.10

6803AP POA6805E3E 10.98

MAB8035HL-6P 5A8MC10103P 1.98

UM9151-3 POA75172NGUPB8238 POA

AD592CN PDAAD594AD 12.64

M7212AM1PL 3.88M72131PD 458

LM3939 0 30LM393P 0.30

OPO7CP 095OPO7EP 3.10

TLC551CP 3.68TLC555CP 015

3.6875173 3.60

00489 024BC490 0.30

MJE340 0.68MJE350 1.10

6810P POA6821P 152 MC10115L 3.21

MCI 011 5P 1.98UPB8282C 498UP88284AD 498

8259582 10.20

AD64"40 M7216A1J1 22.44M7217AIPI 920

LM394CN 5.98LM39992 2.76

OP11GP 5.85OP177FP 3.71

TLC556CN 1.58

TLC7524CN 5.2475174 32075174NG 368

150516 0.2280517 0.20

131E520 0.80MP03638 018

6840P 3.406844868458 4-866845SP 5I4068A0OP POA

MC146805E2P 9.18MC68000P12/113 POA13068010810/12 POAMC6802P 2.47

UPB8286C 4.982.60UPD70108C-10 9 10UPD70108C-0 6.95UPD701160-10 1290

A0707JNA0711JN 214AD712JN 3-72AD7245.1N/KN POAAD741KN 5'65

CM7217BIJI 10 42M72171.11 10.42M7218AIJI 6.85M7218AIPI 885

LM399H 7.85LM4250J 11E2LM55509 a28LM565CN 7.48

OP27GP 2.89OP42FZ 7.44OP77GP 2 07OPO7CN ass

TLE2061CP 220TLE2062CP 3.40TLE2064CN 3.45TLE2161CP 2.42

751757517, 180751766 2.2875,708/. 4.98

BC546 0.05BC546A 0.05605466 0.05130547 008

MPSA06 0.12MPSA13 0.12MPSA53 0.32MPSA92 024

688098 4.30688218 198

MC6809P 878MC6821 P 1.80MC6840P 5.05

UP2701160-8 9.200PD71055C 4.38UPD7201AC 11.68

A07523KN 9 80AD7537JN 32.98

M721801J1 6.85M7218EUL 14.76

CM7224IPL 898

LM710CH 2.80LM7230H 2E07M723CN 0.70

PM7548HP 18.20RC413654 0.98RC4193N POA

TMS3477NL 5.96TPIC2406NE 7.14TPIC2802KV 8.40

75177 2.6078178 2 6075182 2.60

805478 0.08005476 0.08BC547C 0.08

MPS005 2.21

MTP8P08 2.8000147 1.80688408 2.56

68A5OP 2.9813068448 18.40 UPD7201C 6.802.60AD7537LN POA

AD7542KN POAM722681.13 2E12 LM733CN 2.65 RC4194N 2 85 TPIC62599 3.28 75183 BC548 0.08 0019 1.85

68809P 198 M06845P 7.38 UPD765AC 5 42AD7543JCWE POA

M722651PL 23.54 LM7410J-14 220 R04207GN 1 92 TP1C6273N 328 75188 0.40 BC5488 0.08 0C45 0.65

680218 1.968MC6850P 3.35 UP2765AC 5.42

AD7578KN 46.15M72491DM POA LM741CN 045 R04558 0.90 TP1065959 328 75189 0.85 130549 0.08 0072 a80

688401628

8080A 496

M068705R3P 25.35MC68AOOP 7.02

UP0780C-1 4.76UPD80C39HC 8.4228480844AN 875ADC0804LCN 420

0M75551BA 240CM7555IPA 0.84

LM747CH 2.40LM747CN 090

904558P 0.60REF01 CP 3.33

T0C426CPA POATSC500CPE POA

751898 0.8578381

805498 0.08130550 0.08

0078 0.800091M aeo

808584-2 5..98M068A09P 7.62MC8314P 6.60

UPD8155HD 5.84CM7556IPDUPD8251 AFC 4.08 ADC0820CCN 22A0

1.85M64031PL 10E0

LM7800P 2.40LM79GCP 2.40

REFO1HP 3.33REFO2CP 3.98

TSC7106CPL 6.81

TSC7116CPL 5.2575365 2.7278487A 3.26

BC550B 108BC550C 0.08

0081Z 0.92PN3643 0.188086 3.40

8086-2MCM6810P 3.00 UPD8253G-2 3.32 8200834009 10.80

ADC804LCWM 12.10L272 2.10 LM833N 2.82 REFO3GP 3.69 TSC71260PL 535 784808 664 BC556 aoe T10106%4 078

80028612/8ga 485080C286-8/plcc 24.4080085A 4 95

MCM68A1OP 5.35MM532009 3.40MM581678N 10.64

UPD13253C-5 3.32UPD8286C POAUPD8741AD 12.52

13.98

ADC84KG-10 12 66ADC908HP 1 2A5080809 POA

L272M a10L293E 3.90L297A 4.69

LS285AB 240LS288B 3.60LS7210 9.40LT1006CNB 2.72

REF25Z 1.12025608 POASAA1027 6.51

TSC7660CPA 1.40L110968 4.92U20666 2.64

75451754518 04875452 028

005568 0.08BC5566 0.08

60557 0.08

TICP206D 0.61T1CV106D 024718115 0.55

800858.2 5'94MM581748N 14.80 UPD8749HC

ADG201AKNL4805CV 220

4.58SA51043P 7.98 U24006 5.56 7545215 048 005570 0.08 TIP121 0.68

8118-5CH 760 13135827401' 9.18 720.10MHz 9.10ADOPO7CN 2.32

L487 3.15 LTIOIOCT 58830498 992 U6648 5.95 75453 0.64 00558 0a8 718145 1.37

93L34DC i08 MSM5832R5 3.39 720-8MHz 6.95L496084001502 17.20

3.15 LT1028048 7.32 SAA502513 7.65 UA2240PC 1.40 754538 0.64 80558A 0.08 TIP2955 0.88

AM25LS258819 2'88'

MSM80C35RS 4.90 V30-10MHz 12.90AY -3-1270 3.60

L7028 2.94 LT1032CN 4.70 58860028 10.80 06709CP 0.85 75,4 0,64 BC55813 0.08 TIP30 0.48

AM251_52569P 2.68MSM80C39/SMD6.45 730-8MHz 9.20

AY -54013 3.20LA6250 POA LTI 070CT 9.14 SA55605 3.40 UA709PC 0.85 75,48 0.98 BC559A 0.08 7183055 0.88

AM2602PC 2'30AM26LS31DC 2 30

-

MSM80085A 3.95MSM80C85A-2 5.98

7610308 7.80

VC0106146 8.60 AY -5-1013A 5.24AY.3-1015D 3 60

4A8358 POA,...,88.,0 POA

LT1083CP 8.82LT1086CT

SED2000FVA 9.60SFC2301ADC 6.78

UA715HC 4.50UA723CP 0.70

7,82 0.9875483

1 10

BC559B 0.08

BC260A 008TIP31A 0.38TIP328 0.40

813264$31 PC 1 26AM275191 ADC 10.20

MSM80C86 7.60MSM81C55 4.60

Z0800110PSC 16.90Z0868112PSC 3.20 AY -5-1250 POA

AY -5 -3600 -PRO 9.96

L885.20

LC7132 POALTC1052 7.97LTC485CN8 2.16

SFC274113CSG3524N

UA733CJ 2.9875,88UA741MP

3.6075469 1 30

BC560C001840 0.08

TIP47 0.8072751A10 0.92

AM275281PC 625.8132964620 12.36

MSMB2C51A 3.58MSM82C53-2 3.98M5782C53-5 3.58

Z180-MPU POAZ8001B-CPU 11.96Z8018008VSC 8.25

1386109 1-68BA6208 1.40

LC7522 POALC7555 POALD111ACJ POA

470490 4.40M5218AL POAM5220 POA

51766001 1.92SU 452 6.7SL2364C 3.97

UA741TC 0. 8UA748CP 0.36

UA748TC 0.52

78470 POA75471 1.6878472 148

130771 0.2282131 am80135 0.44

11'010453 0927966AF0 140799085 2.96AM296500 6.36

AM2966PC 3.98MSM82C59A-2MSM82054-2 4.20 2808 -CPU 1.25 083048 051 LF13508D 18.20 M5238L POA 5431176 POA UA77000UIC POA 78473 1 48 022418 0.98 VP0104443 092AM29826DC

3.98 Z80A-CTC 166 CA3046(SMD) 0.89

083054 0 54LF311H 10.80 M5298P POA 5448628 2.98 UA798TC 3.80 78474 225 130242C 0.52 VP0104N2 0.98

8M68504 8213513820848 3.30 Z808-D8RT 3.15

CA3059 1.20LF347N 2.40 M706131 1.25 5449028 2.80 UCN5800A 2.40 75477 2 10 152243 VP010493 0.92

AM8238PCMSM82C84/4.2 3.60 Z80A-DMA 195

CA30713AT 2.42LF351N 0.98 MAX1232CNG POA SL56002P 3.00 UCN5801 A 2.60 75491 0.68 BD516 0. 8 ZTX212 0.18

AM9050000 95MSM82C88 12.60 Z80A-P10 1.28

083079 "8LF353N 086 MAX1232CPA 3.57 SL627000P 3.30 11092981A 2.00 75ALS176 2.88 60675 ZT9237 0.26

AM9050CPC 608139102080 2

N80028810/9 24.50N1800286.120 29.54

Z80A-510/0 3.4028013 -CPU 1.52 C83080E 0'70

CA3081 0'66

LF3559 1.82LF356N 1.82

MAXI 259CPE POAMAX162ACNG POA

546700028 5.47SN5281CN POA

00N2982A0056118A 1.6575ALS193J

75845192 2.883.22

130676 0.52

00679 0.54ZT 0.18Z7X313L 028

AM9114BOM 9.980428643C2/p136.20 Z80B-CTC 3.00

CA3089E 422LF357139 4.98 MAX232ACPE 4.84 SN55451BJG POA UGN3501M 7501154 2.88 82680 0.56 ZTX320 a38

AM9551PC N82359 3.68 2808-DARTLF357M/SMD5.80CA3094AE 2.16

498 MAX232CPE 2.80 SOC12 0.20 ULN2001AN au 75014082.73 827430 1.90 270510 0.18

AM96L02PC 3.35AY.543136 6.45AY -5-81313-006 6 45

N82649 3.68N825126AN 3.259825181F 10 04

ZEI0B-DMA POA28013-PIO 2.20

4502808-510LF411CNCA3096AE 3.480830960E 182CA3097E 2E0

LF357N 120LF398N 3 98

1.48

MAX232EWE 380MAX2329 2.80MAX280CPA 6.94

SPI648DG 5.53584534 POA58474028 446

ULN2002A 0.44ULN2003AN 0.44ULN2004AN 1.40

75,185 3.98

75G188 1 2075,188.8 1.32

BDT85 1.126006715 2.7813D796 3.60

IC SOCKETSLOW PROFILE

C1164.6MD ii1198

C82318 59.00C8253CA8008515

9516450N 4.68NS16550AFN 12.60N508009-1 10.80P8032AH 4.29

Z800008B6 2.98CA3120E P08CA313OBT 1920.CA3130E 1.100831408E 1.34

LF412CN 108LF441CN a75LF442CN 0A9LF444CN 2.71

MAX452CPA 5.38MAX627CPA 2.98MAX660CPA 572MAX690ACPA 6.58

SP86290P 3.4458866028 4.96TA7215P 7.20TA7256P 2.60

ULNI2024A 1.40ULN2032A 140ULN2803AN 0.84UM5100 POA

750189AD 1.3275400176 260

BF195.0 0.088E199 0.22BF200 0.16BF2566 0.38

No. Pin Gold Tin Goldof spacTurn 95r sldrPins -mg Pin Tail Tan

TELECOM & SPECIAFUNCTION ICs

6200890-018 370TRANSISTORS

0282085 662 P8051AH 11 20 707W02020 525 CA3140E 0 44LH0002CN 10.80 MAX694CPA POA TA7368P POA UM5101 3.80 THYRISTORS

BF256C 0 38 6 D.3 18p 6p 18p

0082086H-5 9.74CG80C286-12 48.50C080028816 65.00COM8136 6.45COM81C17 11501:32C54 6.42CRT -8004-001 065058205 892

8805284/Basic 23.45PE1080A 3.90P80858-2 5.98P8085811-2 5.9888088 4.80P80C31BH 4.54P80086AL-2 12.60P81554/2

733W50124 5.25AMA1503GX13 4.6813881505 1.80CLA25106/PLCC 5.95GA050010015 3.20KS-49258/PLCC 5.92MJ1454BB 7.65M05175N 3.80

C83146E 090083160E 1250832400CA3240E1 20.9168

-

08324ECA32608

0.981.68

CA3280AE 5 94083280E 3312

LH0032CG 33.60LM101AH 5.65LM100N 9.24LM1I 1H 6.74LM136009 3.40LM1370051 3.40LLmM139

139119

3.408.60

MAX697CPE POAMAX7219CNG 7.15MAX8211CPA 2.28MAX901BCPE POAMC1377P 4.93MCI 413P 0.74MC14411P 11.38MC14416L 17.60

TA7658P POAT878005AP POA78820084 POATA8410K 2.80TA8449P POA78865981' POA7888618TBA120.5 0.60

XR2211CP POAXTR110KP 9.9511112131 4.60291445 go,ZN414Z 1.0429415E 1.84

ZN423 220ZN425E-8 5.97

8 TRIACS SF259 0.40BF324BF421BF450 0.20BF451BF494

0.220.16

8E759 0.26BF961 0.68

8 0.3 18p 6p 18p14 0.3 31p Sp 31p16 0.3 33p 10p 33p18 0.3 39p 1 1 p 39p20 0.3 45p 12p 45p22 0.3 54p 14p24 0.3 54p 14p24 0.6 54p 14p

40406 160.40673 2.401301078/13 0.17130106A/15/C 0.17BC109B/C 0.18BC140-16 048

D3232 5.60P8185 18.10 00-147-7 2.40 085550E 020

LM1458N 0.82 M014495P 4.82 7082400 POA 2N426E-8 3.68 EIC146t01 0 58BF981 28 0.6 80p 16p

D8086 5.48P8205 2.00 8B2352303 4.35 087410E

LM14969 295 MC145406P 2.10 TB8570 POA 7N428E-8 6.95 BC149 0.406E982 se 32 0.6 65p 22p

D8086-2 8.0008202A POA

P821288226 2.40

84340108 6.8004704LM188193.60

0180S5503-KD POA

PC18

LM1801N 7.

4.80MC1455P 0 40MC1455P1 0.60

TBA820MT POA168920 POA

ZN429E-8 264ZN449E 4.76

BC157 0.3450158 0 34

BFG65BFR53-2GHz 0 48

40 0.6 70p 22p" 0-6 85p

08254-2 142 P8251A OMV16BP5 7.980079256016903 P08

LM1889N 7.40 MC1458P 0.32 TBA990 POA BC169C 0.14 BER91-5GHz 0.90 64 0 75 2609

082848D8288 148D820284-12 9.60

P8253 2. 0

P8255A-5P8259 2.8

OMVI8C 6.95OMV18CN1 7.85OMV18CW1 7.85

D800800LCN 410DAC0832LCN 10.67DACO8CP 2.60

LM1894N 4.16LM218H 15.754132391' 3.90

MC1488L 2.40MCI 488P 638M014898 0.80

TC91066P POATCA335A POA708965 POA

60179 a24BFR91A-6GHz 120 64 0.9 260p

PERSONAL COMPUTER - HARDWARE& SOFTWAREVESA LOCAL BUS (Without CPU & DRAM)0820284-8 7.85 320P8259ALM2901QMV25C DACO8EP 164

N 1.25 MC1489AL 2.25 TCM1520AP POA MOTHER BOARDS -

D820288-10 1am P8274 9.98OMV62AW1 69.9042 DAC1008LCN 10.73

LM29039 1.25 MC1489AN 0 80 TCMI 531P POA Processor Chip BIOS Cache Max Expansion BoardSize Pirce

D820288-12 11E5D820288-8287484 9$AA502513DM96019DP822851DP8238N 6.36DP8304BN 2 34

P8279-5 3.20P8282 2.64P8285 3.60P82054P82054-2

4.10

PALI 048CN 190PALI 2H6CN 1.90PAL16R4BCN 2.17

S4534-AMI 420SA336931 2,95

5.40SCM66115P 3.4056578050 4.55SP1450B 5,76ULAIRB029E1 6.80

DAC1222LCN 20 40DG201ABK 3.83DG211 1 56DG508ACJ 3.980050801 125DS148851 0-36DS14C88M/SMD 1.65

LM2904N 425LM2917N-14 6.10LM291751-6 5.80LM29400T15 2.95LM29400T5 2.50413290407 7.50LM301AN 0.36LM30714 1 39

MC1489L 2.20MC1489P 0.38MC14959 2201301550E 332M01648P 12.401301 6588 1278MCI 709CP1 1.20MC1723CP 1.20

TCM1705AN POATCM31059 9.42T0M50879 2.40TCM5089,4 2.401081083 2.6072810858 ass72810850 3.80TDA1151 1.10

Intel Set RAM Memory Slots in mm £ p

804865X/0X/2X2 SIS AMI 128K 32MB 756(87).2032(73E0 260 x 220 120.00804860X/DX/002 SIS AMI 256K 32MB 7x1IBATI.2x328/ESA) 260 x 220 129.00

MICROPROCESSORS CO -PROCESSORS80286-16MHz INTEL £65.00 80287-8 INTEL £40.0080386DX-40MHz AMD £75.00 80287-10 INTEL £48.00

DP83119 6.54251 221 6.44D51231-20 4.44051232 3.260034865 3.20D53487N 320

PAL2ODOCNS 4.35PAL20X8CNS 3.32PALCI6L8Q-2520

5.10PALC20U3Z-45COS

ULA2ORK008E119.72XR-75683 3.60ZNA2L029J-BS 3.802NPCM1J135 8 95

OPTOELECTRONICS

00140886 1.6500140898N 1.65HAI 2017 1.44HA13426 11.964817723 1.10HD75189P POA

LM308N 1.65LM310N 2.98LM31114 0.64LM3119-14 2.15LM312H 8.95

MCI 741CP 045MC3242AP 7.5413033018 0.88MC3302P 0.60MC3340P 1.60

TDA1170S 2.80TDA1515A 4.98TDA1521A 4.37T281 576 3.90TDA1578A 3.60

8048650-25MHz INTEL £115.00 80287 -XL INTEL £62.008048600-33MHz INTEL 6245.00 8038750-33MHz INTEL 662.0080486DX-50MHz INTEL80486002-66MHz INTEL

£ 66 MEMORIES£ 00 SIMM 1Mx9x9 CHIP 7Ons P.O.A.

CONNER HARD DISK DRIVES SIMM 1Mx9x3 CHIP 70ns P.O.A.

DS34C86N 4.80DS34C079 4.80CP54 7

PALC22V10H-35054N25 0.60

8EF4754V 22.20811-0201-5 3.60

LM3I 7AT 260LM317T 0.52

MC3357P 3.20MC3403P 1.40

TDA2595 a 32TDA3048N 1.85

SIMM 4Mx9x9 CHIP 7045 P.O.A.CP-30174 170MB 19msec 3.5' LP £165.00SIMM 4Mx9x3 CHIP 7Ons P.O.A.30254 250MB 15msec 3.5" LP £212.00

DS36319 3.334926D536329 281

8.34PCD8584P 8.28 0.60 HI I -508A-5 1121

LM317T-SGS 052LM318N 2.98

MC3446AP 675MC3479P 7.92

TDA3505 POATDA3810 POA

SIMM 256Kx9 CHIP 8Ons P.O.A.CP-30344 340MB 13msec 3.5' LP £29600

DS3633N PCF8566P 8.28PCF8566T 8.28

41'35 0.404538 056

HI1.549-5 POAHI1-574AKD-5 42.50

Lm310, 284LM32OLZ-12 0.34

MC3523U 5.80MC4024P 12 78

TD8440 P08TD84510 3.38

SOFTWAREFLOPPY DISK DRIVES MICROSOFT ORIGINAL

053634N 2.81DS3691N 4.9600386214 7'38DS5000-32-12 47.50

PCF8570PPCF8573PPCF8574P 5.90

69139 1.60CNX36 0.38

06517-3 0.64CNY21N POA

1113-0201-5 3.20H13 -0509A-5 7.15HI3-201.5TEAL320HIILI P08

LM324AN 3.664133241 2.47LM3249 0 64

MCT2 0.84130761 1.18MF1OCCN 885

TDA4563 3.38TD84660 POATDA7010T POA

ALPS 0E87333243 1.44MB 3.r 130.00 WINDOWS 3.1TEAL FD -2351 -IF 1.44MB 3.5' £30.00

FD-55GFR 1 2MB 5.25' £35.00MITSUBISHI MF355C/258MG 1.44MB 3.5' £29.00

06100

IMPORTANTAll prices quoted are

00136406 120DS8820AN 295

PCF85747PCF8591P 9.35 DF°8 0.40

HCPL-2200 598110574 -AK 18.20CL7104-16CPL 26.08

LM325N 9.40LM3301N 2.60

ML924 4.90MM53099 5.76

1E737052 2.52TDA8702 622

MITSUBISHI MF504C/318MP 1.2MB 5.25' £3500 Excluding V.A.T.

008832/4 R6502AP 5.70

R6520P 4.40 HCPL-2231 5.98 CL7107COH/PLCCLM3342 2.20 MM53105N 4.98 TEA1045 POA GRAPHIC CARDS Postage & Packing

0088361.100883714 2.40 R6522 4.40 HCPL-2602 5.68

HCPL-2630 3.685.20

CL7109CPL 9.85

LM3352 2.48LM336Z-2.5 1.48

MM80C95N 1.44138757012 POA

TEA1060 420TEA5620 POA

CIRRUS .5324 ov915 VI. -BUS Window Am!. W: I MB I:75.00TRIDENT TVGA 89000E New Trident 1MB SV6A£40.00

Charge of 63.00 isapplicable to all goods

DS8838N 2.40EF6803A-116 380

R6522AP 5.80

R65CO2P2 5.84R65CO2P3 6.90

HCPL-2730 3.45HCPL-2731 3.20

CL7116CPL 6.740L71170PL 674

LM3362-5.0 1.48Li3337, 1.15

MUX24E0 160MUX24FP 9.60MV500DP

TIPC2801KV 840TL026CP 1.84

TSENG LAB ET -4000 1MB SVGA £60.00

KEYBOARD & MICE

under the heading of'Personal Computer

EF6803P 3.80EF6821P 1130

R65CO2P4 805R65C102P2 665

HCPL-4200 5.98ILD74 1.44

CL71260PL 674CL7135CPI 8.98

LM339AN 2.98L13330N 0.60LM340AT12 108

105MV601D8 3.36MV8870DP 552

TL062CN 0.52TL062C8 0.52 BTC 7849R 102 UK KB Board. Regular Size£24.00

IMSI SYSTEM MOUSE 3 Button Serial £10.00

Hardware & Software'.

EF68B09P 3.18EF68821P 1.44

R65021P2 5.94 ILO1 1.60IL074 2.25

CL7136CPL 894CL7137CPL 6.94

LM3407-5 0.48 NE50209 1a84TL064CD 0.98TL064C9 0.88 Znix 3 BUTTON MOUSE MS COMPATIBLE 10.00

Postage & Packing willbe charged at cost for

EP610PC-35 POAR65C22P2 4.80

'0074 2.25 CL7606CJN 1224LM340T12 0.48 NE5275 3.71 TL06410/SMD al I/0 CARDS all destinations outside

SA080032P 5.95 LM340T15 am NE532N 060 TL071A0P 1334 IDE 2HD/2FD/2S/1P/1G with cables £15'00 the United Kingdom.

PLEASE SEE PREVIOUS ISSUES FOR OTHER ITEMS & FEB/MAR 1992 ISSUES FOR LEDs,DISPLAYS & RELAYS.

VIEWCOM ELECTRONICS PLEASE ADD £1.10 P & P and then 17.5% VAT. OFFICIAL ORDERS from Govt. & Educational Establish-ments are accepted. VAT at 17.5% is chrageable to all orders received from EC Member Countries unless

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10

800535 HARDWARE/ASSEMBLERCOURSE

PART 1: NTRODUCTION AND FIRST PROGRAMMING EXAMPLES

Welcome to the first instalment of a four-part course onprogramming the 800535 microcontroller. The present 'short'course is a sequel to the eight -part 8051/8032 assemblercourse featured about two years ago in this magazine.Hardware and software peculiar to the 800535 processor willbe discussed in an educational/didactic way, based onexamples: an assembler and a communication program areavailable as 'courseware' on a diskette. The hardware you needto follow this course is the 800535 single -board computerfeatured in last month's magazine.

Software by Dr. M. Ohsmann

HE present course has an 'easy'THE level for those of you whohave followed the 8051/8032 assem-bler course (Ref. 1), because both themonitor EPROM (EMON51) and the as-sembler (EASM51) can be usedstraight away on the 800535 single -board computer described last month(Ref. 2). None the less, a new, extendedmonitor program and assembler weredeveloped to take full advantage of theextra features offered by the 800535compared with the 8051. These extrafeatures are summarized in Table 1.The new monitor and assembler are

called EMON52 and EASM52 respec-tively, and may be found on thecourseware disk, order code 1811 (seeReaders Services page). Note in partic-ular that the new software supportsthe Intel Hex file download option,which is a big asset if you have anEPROM programmer which is compati-ble with that file format.

The way ahead: 800535The 800535 is an Intel MCS-51 com-patible derivative of the 'generic' 8051.The SAB80C535 is manufactured by

II Improved assembler (EASM52), offering- Intel -Hex file download option;

DW command to generate 16 -bit address constants;- DI command to generate 16 -bit integer constants;- EQU command capable of processing bit operations.

II A new system monitor (EMON52) offering- 800535 and 800537 interrupt chaining;- Intel -Hex file downloading.

A new PC communication program (V25COM) source code, offering- an Intel -Hex file download option.

EPROMEMU, a program to support the Elektor Electronics EPROM Emulator II.k A new MENU program for fast object code development and downloading.

Assembly code (.A51) files of all example programs discussed during thecourse.Complete source code files (Turbo Pascal or MCS-51 assembler) of all utilityprograms.

Table 1. Overview of new features on the 800535 course disk.

Siemens, and has a number of extrafeatures over the 8051. To start with,the C535 has two additional bidirec-tional ports, P4 and P5. It also offersan analogue input port sporting eightinputs and a common 8 -bit analogue -to -digital converter (ADC).Remarkably, this port may also beused as a digital input port.

Furthermore, there is a powerfultimer and compare/capture unit. Theavailable interrupt options have beenconsiderably extended, and a new bau-drate generator has been added. Thepolarity of the RESET signal has beenchanged from positive on the 8051 tonegative on the 800535 (pin 10).

The new features are introduced inthe following sections, using exampleprograms where appropriate.

Some of you may wonder why wekeep referring to the 800535 proces-sor, when it is a derivative from theòriginal' 80515 or 80535. Unfortu-nately, the NMOS 80535 and theCMOS SAB80C535 are not pin -com-patible. Pin 4 (PE) and pin 37 (Vcc)have different functions on the 80535.For all other functions, the C535 andthe 535 are, however, virtually identi-cal, with the exception of the POWER -DOWN and IDLE modes. In this coursewe restrict ourselves to the 800535.

SFRs, power -save andPCONAs with other ùpgrade' versions of the8051, the new hardware options of the800535 are realized by special func-tions registers (SFRs). The SFRs con-tained in the 800535 are listed inTable 2. Note that some of the SFRsfamiliar from the 8052 have been re-named, although the òld' name is alsogiven.

The CMOS 800535 processor offerstwo ways of reducing power consump-tion, which are of particular interest ifthe controller is used in battery -oper-ated equipment. To actuate the power -save modes, certain bits must be set inthe PCON special function register.The meaning of these bits is illustratedin Fig. 1.

The IDLE mode allows the CPUproper to be actually halted, while theperipherals, like timers, counters andinterrupt circuits remain active. The


800535 HARDWARE/ASSEMBLER COURSE - 1

SFR PCON (871-1)

SMOD PDS IDLS 1 - GF1 GFO PDE IDLE

7 6 5 4 3 2 1 0

87H

Symbol Position Function

SMOD PCON.7 When set, the baud rate of the serial channel in mode

PDS PCON.6

IDLS PCON.5

GF1

G FO

PDE

IDLE

PCON.4

PCON.3

PCON.2

PCON .1

PCON .O

1, 2, 3 is doubled.

Power -down start bit. The instruction that sets the PDSflag bit is the last instruction before entering the power -down mode.

Idle start bit. The instruction that sets the IDLS flag bit isthe last instruction before entering the idle mode.

Reserved

General purpose flag

General purpose flag

Power -down enable bit. When set, starting of thepower -down mode is enabled.

Idle mode enable bit. When set, starting of the idlemode is enabled.

920152-11

Fig. 1. Functions of the bits contained in the PCON register.

watchdog timer is, however, stopped.The CPU is taken out of the IDLE modewith the aid of an interrupt, which is'serviced' by an appropriate softwareroutine. After the RETI (return from in-terrupt) instruction at the end of thatroutine, the CPU continues with theinstruction that follows the one thatcaused it to go into IDLE mode. TheIDLE mode is controlled by bits 0(IDLE) and 5 (IDLS) in the PCON regis-ter. First, the IDLE preparation bit,IDLE, must be set, then the IDLE -SETbit, IDLS. A sequence of two instruc-tions is used rather than just one in-struction to prevent the IDLE modebeing selected by accident. Since thePCON register is not bit -addressable,

the IDLE and IDLS bits are normallyset with the aid of an ORL instruction.

The POWER -DOWN mode is selectedby first setting the PDE bit, and thenthe PDS bit. In POWER -DOWN mode,the processor is totally 'inert', and canbe actuated again by a reset only. Thedata contained in the SFR and the on-board RAM remain intact. Both theIDLE and the POWER -DOWN mode canonly be actuated if the PE input of the800535 (pin 4) is held low. If not, thesemodes are disabled. The hardware dis-able option of the power -down modes isprovided to eliminate any risk of thembeing selected by accident as a resultof a crashing program. This is, obvi-ously, essential in no -break systems,

5V

Supply

100mA

T1

RESET

GND - K6 Pin 2

+- K6 Pin 1

ANO = K6 Pin 3

800535COMPUTER

K3 Pin 5 = P3.2 = INT Pin

T2 Interrupt

920152.12

V24

K4 Pin 8 2 (3)

K4 Pln 10 3 (2)

K4 Pin 2 5 (7)

To PC9.w sub.025-w sub -0

Fig. 2. Schematic showing the interconnections between the hardware needed to follow thecourse.

800535 PROGRAMMING

You need the following to be able tofollow the 800535 hardware/assemblercourse:

Hardware:An 800535 single -board computer asdescribed in Elektor ElectronicsFebruary 1994.

- Art IBM PC or compatible with a serialport on COM1: or COM2:.

Software:- Courseware disk (5.25 inch, 360K

MSDOS format).- EMON52 system EPROM, fitted on800535 SBC.

The courseware disk and EPROM areavailable as a set under order code 6221.The disk is also available separately underorder code 1:s:1, For prices and orderinginformation, see page 70.

JOIN THE COURSE!

where all hardware would stop func-tioning if the POWER -DOWN modewere selected, and there is no way ofrestarting the CPU except by switchingthe supply off and on again.

Testing the power -downmodesTo be able to use the example pro-grams discussed during this course,follow this procedure:

HardwareConnect the 800535 single -boardcomputer to a 5-V power supply andthe COM1: serial port on your PC asshown in Fig. 2. All jumpers must befitted on the board. The EPROM socketon the SBC board should contain theEMON52 EPROM (order code 6221).Switch on the PC and the SBC.

SoftwareCopy all files contained on the coursediskette, order code 1811, to the harddisk, into a suitably named subdirec-tory, for instance, C: \ 800535 orC: \ COURSE. Next, load the ASCII fileMENU.PAR into your word processor,and change the first line so that it con-tains the name of your favourite wordprocessor ('editor'), complete with theassociated path. The author used theeditor contained in Turbo Pascal. Savethe changed file under its old name,i.e., MENU.PAR.

Next, go to the course subdirectory,and start MENU by typing


COMPUTERS AND MICROPROCESSORS

MENU 535XMP01 (return)

The menu should appear in the right-hand top corner of the screen. First,select 'Assemble', with the aid of thevertical arrow keys, and press return.The first example program is assem-bled, and the files 535XMP01.OBJ and535XMPOI.LST are written. Return tothe main manu, and select the V24(download) option. Press the RESETkey connected to the SBC, whereuponthe 800535 should report with

EMON52 -- version 0.1 (2.7.1992)RAMTOP=44

Next, start the actual download opera-tion by typing CONTROL -D. Start theprogram by entering commandX 4100. Watch the ammeter on yourpower supply. After a couple of reportsreading 'ACTIVE', the 800535 isswitched to low -power mode, indicatedby the text 'IDLE', and the current con-sumption dropping to about 20 mA.Generate an external interrupt -0 bypressing switch T2. This should causethe processor to wake up, and the cur-rent consumption to rise to about40 mA. Shortly afterwards, the CPU re-turns to IDLE mode.

The IDLE mode is initiated by theinstructions contained in lines 25 and26 of the assembly code file535XMP01.A51. Two lines marked bythe label PDOWN could cause thePOWER DOWN mode to be actuated.Check what happens if jumper JP2 isomitted, and the above experiment isrepeated. Or: the interrupt is enabledin line 24, and disabled again inline 27. What happens if you leave outline 27? Press the interrupt key severaltimes while the program runs.Imagine, the main program has justcalled monitor subroutine STXT, is in-terrupted, while the interrupt routineitself calls STXT.

Baudrate generator andsystem clockAll programmers who used the 8051(or 8032) with a 12 -MHz quartz crystalwere unable to have the serial inter-face running at exactly 4,800 baud,because the bit clock was derived fromthe system clock (12 MHz/12 =

1 MHz). This problem is solved by aspecial baudrate generator containedin the 800535. Consequently, onetimer is freed for other purposes. Thebaudrate generator is switched on withbit 7 in the ADCON special functionregister. A simple bit set commandmay be used for this purpose sinceADCON is bit -addressable. As with thebaud rate generator based on Timer 1,bit 7 in the PCON register is used to

PO 80H *SP 81H

DPL 82H

DPH 83H

PCON 87H

TCON 88H *TMOD 89H

TLO 8AH

TL1 8BH

THO 8CH

TH1 8DH

P1 90H *SCON 98H

SBUF 99H *P2 AOH *IENO A8H *IPO A9H

P3 BOH *

IEN1 B8H *IP1 B9H

IRCON COH *

CCEN C1H

CCL1 C2H

CCH1 C3H

CCL2 C4H

CCH2 C5H

CCL3 C6H

CCH3 C7H

T2CON C8H *CRCL CAH

CRCH CBH

TL2 CCH

TH2 CDH

PSW DOH *

ADCON D8H *ADDAT D9H

DAPR DAH

P6 DBH

ACC EOH *

P4 E8H *B FOH *

P5 F8H

Port 0Stack pointerData pointer lowData pointer highPower control registerTimer control registerTimer mode registerTimer 0 low byteTimer 1 low byteTimer 0 high byteTimer 1 high bytePort 1

Serial control registerSerial bufferPort 2Interrupt enable register 0 (1E)Interrupt priority register 0Port 3Interrupt enable register 1 (IP)Interrupt priority register 1Interrupt request control registerCompare/capture enable registerCompare/capture register 1 low byteCompare/capture register 1 high byteCompare/capture register 2 low byteCompare/capture register 2 high byteCompare/capture register 3 low byteCompare/capture register 3 high byteTimer 2 control registerCompare/reload/capture register low byte (RCAP2L)Compare/reload/capture register high byte (RCAP2H)Timer 2 low byteTimer 2 high byteProgram status wordA -D converter control registerA -D converter data registerD -A converter program registerPort 6AccumulatorPort 4B registerPort 5

Table 2. List of 800535 special function registers. The SFRs marked with an asterisk (*) arebit -addressable. Where appropriate, the corresponding 8051 SFR denotation is given inbrackets. SFRs marked with a plus sign (+) are new, or have been assigned new functions.

ADCON EQU OD8HPCON EQU 087H

B4800 ANL PCON,#01111111B ;clear bit 7 in PCONSETB ADCON.7RET

B9600

;baudrate generator on at 4800 bd

ORL PCON,#10000000B ;set bit 7 in PCONSETB ADCON.7RET

;baudrate generator on at 9600 bd

Fig. 3. EASM52 listing of baudrate generator test program.


A A p

6.00 UOSCILLOSCOPE LIVE CHOP Page 0.00

46.6 U

A4.u0 4uA.0 0

2.00 / 4.0 psec 33,3

0.0010.0 psec

26.6msec20.0

-2,00 50.0 msec 20.0

-4,000.1

0.2

msec

msec13.3

-6.00 0.5 nsec 6.66

-8.001.0 MSEC

nsec0.00

2.0

-10.0 5.0 msec .6.66

t.00(psec) 12.00 10.0 msec

20.0CH2 S

50.0

msec

msecFREEZE ONE SHOT MODE CHI SET

TIME/DIV TIME-MAG, TIME-OUT j HYSTERESIS SLOPE0.1 sec CH 1

sec0.2

PRINT COMMENT READ DISK j WRITE DISK

Connect the HANDYPROBE to the parallel printer portof the PC and start the software Measuring can becarried out at once The HANDYPROBE does not needan external power supply Some technical parameters0 5-400 V softwareselect input range,one input channel;8 bits resolution(overall accuracy 2%),A complete softwareprogram consisting ofa digitalstorage oscilloscope,spectrum analyzer,voltmeter and atransient recorderis providedThe HANDYPROBE iseminently suitable forservicing andeducational purposes

The TP5008 is an interface cardthat provides an analogueoutput in addition to two inputchannels This output incombination with the twoinputs may be used for thesetting up of a completecontrol loop The outputmay also be used as afunction generatorThe TP5008 has aresolution of 8 bitsand a sampling rateof 200,000 samples/sec (200 kHz) The input range may be set to 0.5-20 Vfull-scale deflection The output range covers 1.25-2.5 V.The TP5008 is fitted with BNC connectors and isdelivered complete with a user manual and software.Separately available are 1.1-1.10 probesand 1 100 oscilloscope probes 197

TiePie engineering manufactures a completerange of computer -controlled measuring instrumentsConnecting these units to a PC (MS DOS 3 0 or higher)results in a number of compre-hensive test instruments - oscilloscope;

- voltmeter;- spectrum analyzer;- frequency meter;- transient recorder.

All measured data can be storedon disk or run off for documentation Because of themany trigger possibilities, a variety of signals can bemeasured, while the powerful software enables amultitude of measurements to be carried out in astraightforward manner Application areas includeservice, medical research, automatic test systems,research and development, and education

11 I A II

1 P

The HANDYSCOPE is connected to the parallel printerport This makes it possible to carry out measurementswith a laptop or notebook PC Because of its highresolution (12 bits), the HANDYSCOPE is a very accurateinstrument The measuring rate is 100,000 samples/secEither of the two channels can be set independentlyover a range of 0 5-20 V (with a 1 10 probe up to 200 V)The advanced software enables many measurements tobe carried out Two probes (switchable 1 1-1 10) areprovided The HANDYSCOPE is constructed as a smalltable model with two BNC connectorsThe length ofthe cablelinking thePC and theHANDYSCOPEis 18 m,which can beextendedto 3 8 m

The TP208 is an interface cardwith a measuring speed of2x20 Megasamples/sec(8 bits) Phenomena shorterthan one millionth of asecond can still bemeasured wellThe completely digitizedtriggering ensures verystable triggering withmany triggerpossibilitiesThe TP208 has aninput range of5 mV/div to 20 V/div in 12 steps and an auto calibrationfunction Since both channels may be sampledsimultaneously, phase differences can be measuredvery accurately Even single phenomena can bemeasured since each channel has a32 KByte memory Comprehensivesoftware is provided

Interested? Then write or fax for a FREE demo diskette to

INSTRUTEK (UK)28 Stephenson RoadIndustrial Estate

St Ives, Cambs PE17 4WJEngland

595

(All prices are exclusive of VAT and P841,)

Telephone (0480) 460 028

Fax 10480) 460 340

14 COMPUTERS AND MICROPROCESSORS

****** EASM52 ASSEMBLER LISTING (535XMP01) ******LINE LOC OBJ T SOURCE

1 0000 ; 535XMP01.A51 ; Testing 800535 POWERDOWN Modes2 00003 0000 IE EQU 0A8H4 0000 ACC EQU OEOH5 0000 PCON EQU 087H6 0000 P3 EQU OBOH7 00008 00009 000010 0000 ORG 4100H11 4100 90 41 38 [2] START MOV DPTR,#INTO ; Chain interrupt routine12 4103 74 01 [1] MOV A,#113 4105 75 30 40 [2] MOV COMMAND,#ccLINK14 4108 12 02 00 [2] LCALL MON15 410B 79 06 [1] LP2 MOV R1,#6 Send text 6 times16 410D 90 41 49 [2] LP1 MOV DPTR,#TXT1 Text ACTIVE17 4110 12 41 64 [2] LCALL STXT Send18 4113 90 01 F4 [2] MOV DPTR,#500 0.5 sec19 4116 75 30 21 [2] MOV COMMAND,#CcLTIME Wait20 4119 12 02 00 [2] LCALL MON21 411C D9 EF [2] DJNZ R1,LP1 Continue loop22 411E 90 41 3F [2] MOV DPTR,#TXTO Send text IDLE23 4121.12 41 64 [2] LCALL STXT24 4124 75 A8 81 [2] MOV IE,#1000000113 Switch on interrupts EA,IEO25 4127 43 87 01 [2] ORL PCON,#000000018 Prepare for IDLE mode26 412A 43 87 20 [2] ORL PCON,#00100000B and actuate27 412D 75 A8 00 [2] MOV IE,#0 Switch off interrupts28 4130 80 D9 [2] SJMP LP229 413230 4132 43 87 02 [2] PDOWN ORL PCON,#0000001OB ; Start power down mode31 4135 43 87 40 [2] ORL PCON,#01000000B32 413833 4138 90 41 53 [2] INTO MOV DPTR,#TXT2 ; Interrupt routine34 413B 12 41 64 [2] LCALL STXT ; Send text35 413E 32 [2] RETI ; Finish interrupt36 413F37 413F OD OA 49 TXTO DB 13,10,'IDLE...',0 ;

44 4C 452E 2E 2E00

38 4149 20 41 43 TXT1 DB ' ACTIVE ',0 ;

54 49 5645 20 2000

39 4153 OD OA 49 TXT2 DB 13,10,'INTERRUPT E0',13,10,0 ;

4E 54 4552 52 5550 54 2045 30 ODOA 00

40 416441 4164 MONITOR INTERFACE42 4164 COMMAND EQU 030H ; MONITOR: command location43 4164 MON EQU 0200H ; MONITOR: jump address44 4164 ccSTXT EQU 002H ; Send text45 4164 ccLINK EQU 040H ; Interrupt chaining46 4164 ccLTIME EQU 0218 ; DPTR delay in milliseconds47 416448 4164 75 30 02 [2] STXT MOV COMMAND,#ccSTXT49 4167 02 02 00 [2] LJMP MON50 416A END

********* SYMBOL TABLE (18 symbols) **********IE :00A8 ACC :00E0 PCON :0087 P3 :0080

START :4100 LP2 :4108 LP1 :410D PDOWN :4132INTO :4138 TXTO :413F TXT1 :4149 TXT2 :4153

COMMAND :0030 MON :0200 ccSTXT :0002 ccLINK :0040ccLTIME :0021 STXT :4164

Fig. 4. Assembler code listing of 535XMP01 found on your course disk. This program is usedto demonstrate the operation of the two power -down modes of the 800535 microcontroller.

select between 4,800 (bit=0) and 9,600baud (bit=1). The listing in Fig. 3shows how to program the baud rateon the serial interface.

Note that this program takes intoaccount that PCON is not bit -address-able: to prevent the 'other' bits in theregister from being affected, maskinginstructions ANL and ORL are used.

The course diskette contains a pro-gram called 535XMP02.A51 which,when assembled, downloaded and runon the 535 SBC, transmits texts alter-nately at 4,800 and 9,600 baud. If youstart the download program V24 (orthe new version, V25) with the corre-sponding speed parameter (see .DOCfile), one of the texts will be legible. Thebaud rate may be defined either bychanging the appropriate parameter inMENU.PAR, or by calling V24COM (orV25COM), followed by the appropriateparameter, directly from the DOSprompt.

In some cases, peripheral ICs re-quire the system clock (quartz clockdivided by 12). To have the 800535supply the system clock at pin 30(P1.6), set bit 6 in the ADCON register,and write a 1 to P1.6. The latter is nec-essary to enable the output function ofthe port line, which is controlled via aninternal logic -AND combination. Thus,write

SETB ADCON.6SETB P1.6

and take the system clock from theP1.6 line.

To be continued.

References:1. 8051/8032 Assembler course.Elektor Electronics February throughNovember 1992.2 800535 Single -board computer.Elektor Electronics February 1994.

Fig. 5. 800535 single board computer de-scribed in Ref. 2. The board should be fittedwith the EMON52 system EPROM, no. 6221.


100 WATT HIGH -END POWER AMPLIFIER

rrhe simplified circuit diagram in Fig. 11 clearly shows the symmetrical design

of the amplifier. The input stage is formedby differential amplifiers T1, T3, whosegain is limited to about 40 dB (x100). Thestage is coupled to differential amplifiersT2, T4, whose gain is around 10 dB (x3).These amplifiers are linked via optoiso-lators to drivers T12, T13, which form thelink between the input and output stages.The zener symbol between the drivers in-dicates a variable zener transistor, whichenables the accurate setting of the qui-escent current through the output tran-sistors. The output stage consists of tran-sistors T18 and T17, each of which drivestwo parallel -connected power transistors:T18, T19 and T20, T21 respectively.

The optoisolators provide suppressionof the on/off switching clicks, which, owingto the absence of an output relay, is es-sential. The POWER ON DELAY (which is partof a protection circuit on a separate PCB)ensures that the LEDs in the optoisola-tors light up only gradually after switch -on.Consequently, the optotransistors in thecollector circuits of T12 and T13 come intoconduction slowly, resulting in the powersupply to the output transistors buildingup gradually. This arrangement effectivelyprevents annoying clicks at switch -on.When the mains is switched off, the LEDsgo out rapidly, resulting in an abrupt re-moval of power from the output transis-tors. Consequently, the output stage getsno time to produce irritating switch -offphenomena.

The protection circuit uses no relayand relies on the current through theemitter resistors of the output transis-tors and the output voltage for correct op-eration. If, for whatever reason,the cur-rent rises unduly or a direct voltage ap-pears at the output, two actions take place:the optoisolators are cut off, so that thepower to the output stages is removed in-stantly, and the supply lines are shortedto earth with the aid of triacs, A some-what drastic, but very effective and reli-able means of safeguarding the amplifierfrom compression and distortion at largedrive voltages.

Not shown in Fig. 1 is a thermal pro-tection circuit, which, again via the op-toisolators, removes the power from theoutput transistors if the temperature ofthese devices rises unduly.

Amplifier circuitThe circuit diagram of the amplifier (singlechannel) in Fig. 3 is, in large parts, sim-ilar to that of the 'Output amplifier for rib-bon loudspeakers' (2). The differences lie

Design by T. Giesberts

This article describes a completely updated and higher -powerversion of the 'Medium power a.f. amplifier' published in this

magazine just over three years ago(1). At the suggestion ofmany readers, the new amplifier also incorporates a number of

features of the 'Output amplifier for ribbon loudspeakers'published two years later(2). It provides 100 W into 8 CI and does

not use an output relay.

TECHNICAL DATA

Input sensitivityInput impedanceOutput power (0.1% THD)

Music power (500 Hz burst: 5 periods on,5 periods off)

Power bandwidth (50 W into 8 C2)Slew rateSignal-to-noise ratio (1 W into 8 12)Harmonic distortion (B = 10 Hz - 80 kHz)

at 1 W into 8at 90 W into 8 n

Intermodulation distortion(50 Hz : 7 kHz; 4 : 1)

Dynamic 1M distortion (block 3.15 kHzwith 15 kHz sine wave)

Damping factor (8 SI output)

1 V r.m.s.46.5 kfl100 W into 8 SI175Winto4Sl105 W into 8 SI185 W into 4 521.5 Hz - 220 kHz>50 V ps-1>102 dB (A weighted)

<0.0025% (1 kHz)<0.0015% (1 kHz)<0.015% (20 Hz - 20 kHz)<0.002% (1 W in to 8 0)<0.003% (50 W into 852)<0.0025% (1 W into 8 S2<0.0015% (100 W into 8 S2)>1000 (1 kHz)>290 (20 kHz)


16 AUDIO & HI -11

Fig. 1. Simplified circuit diagram of the amplifier (one channel).

15V15V

30V 0

02

30V 22

15V

1 N4004

IC1

TemperatureC R18

0

CI

2/205J5V

mimBC 00n

547B

220, 16V

MEI

BC547B

1N4148

BC516

1 N4001

2xBC557B

T5

BC547B04 01311

08

D7 1N4148

194148

BC547B T,0

C10

220n

1N4148

7

IC2

7805

to-

BD140

61 82

0+15V 1130 131

OT T

TIC263M

BD679

2205

R29

22052

Al

0®Al

Tri2

TIC263M 92

1132 133

930039 - 13

5V

Fig. 2. The protection circuit does not use relays.

mainly in the much higher supply volt-age (2 x 42 V instead of 2 x 15 V) and themuch lower peak output current. Other,smaller, differences are a number of al-tered component values, new types oftransistor in various positions, lower valuefuses, fewer parallel -connected emitterresistors for the output transistors andan additional capacitor, Cp3, in the feed-back loop. Also, the separate sense linesto the loudspeaker(s) are no longer there,and the connections between IC3 and thesupply lines have been broken (D9 andD10 are omitted), because the supply volt-age for the DC correction is now providedby an auxiliary supply.

At the input, there is a combination ofa high-pass section, C1 -R1, and a low-pass section, C2 -R2. The first filter pre-vents any direct voltage entering the ampli-fier, while the second restricts the upperlimit of the input bandwidth to about300 kHz.

The signal is applied to differential am-plifiers T1 and T3. Since the maximumpermissible supply voltage of the excel-lent dual transistors MATO2 and MATO3is too low, these types had to be replacedby a 2N2914 and a BFX36 respectively.Frequency compensation of the inputstage is provided by networks R5 -C3 andR10 -C4. The open -loop bandwidth of theamplifier is around 14 kHz. The gain ofthe amplifiers is determined by the ratioof their collector and emitter resistors.

Current sources T5 and T6 guaranteestable operation of Ti and T3. This is aug-mented by the arrangement of holdingthe current through reference LEDs D1and D2 stable with the aid of a third cur-rent source: T9.

The next stage consists of dual tran-sistors T2 and T4, which are controlled bycurrent sources T7 and T8. Again, the cur-rent through LEDs D3 and D4 is held sta-ble by current sources T10 and T11.

Diodes D1 -D4 must be of the same typewith a forward voltage of 1.55-1.65 V toensure that the operating points of thevarious transistors remain unchanged.

The optoisolators for the power -on delayare inserted in the collector leads of T2band T4b. Their LEDs are controlled by theexternal protection circuit via B1 and B2.

The collectors of predrivers T12 and T13are connected via T14 and T15. The lattertransistors form a zener transistor, thevoltage across which, and thus the qui-escent current through the output tran-sistors, is set as appropriate with P1.

Each of the two halves of the outputstage, a super emitter follower, consistsof a driver, T16 and T17, and two powertransistors, T18, T19 and T20, T21 respect-ively. The power transistor pairs are con-nected in parallel, but have their ownemitter resistors. Transistor T22 monitorsthe voltage drop across the emitter re-sistors via potential divider R44 -R45. If thetotal peak output current exceeds 18 A,T22 switches on, which causes the exter-nal protection circuit to be actuated.


100 W HIGH -END POWER AMPLIFIER IA 6.3 A fuse has been incorporated in

the collector line of each of the power tran-sistors. The + and - taps in these linesare connected to the triacs (+ and -) inthe protection circuit-see Fig. 2. If the

fuses blow, D5 and D6 light to indicatethis. In practice this will happen hardlyever, because the primary fuse will almostcertainly blow first.

Boucherot network R47 -C12 ensures

that the amplifier remains loaded ade-quately at high frequencies.

Output power is supplied to the loud-speaker(s) via inductor LI, which limitsthe rise time of the signal when the load

Fig. 3. Circuit diagram of the amplifier (one channel). The double dashed lines (e.g., D1 -T5) indicate that thermal coupling isrequired. Transistors T14 -T21 must be mounted on a common heat sink.


18 AUDIO & HI-FI

is capacitive, and potential divider R48 -R51.The ratio R49: R50 determines the feed-back factor. The feedback voltage at thejunction of these resistors is applied tothe bases ofTlb and T3b. Capacitor Cfb ac-celerates the action of the feedback cir-cuit. Network R75 -R76 -C23 -C24 serves to

keep the base impedances at the left-handand right-hand halves of the differentialamplifier equal to ensure optimum com-mon -mode suppression.

An additional stabilized voltage is pro-duced with the aid of IC4 to limit the off-set voltage at the output to a minimum.

0-0

POWER ONDELAY

0-0

Tr1

2x 30V

300VA

R1 R5

5W

B1 = B200C35000

R3

R4 5W

(:75W

ESER6 5

ESE5W

C1 C20 010m 10m50V 50V

C3 C40 010m50V

10m50VR7

DTIR8 5

EEI5W

42V

-C)42V

930039 - 15

Fig. 4. Circuit diagram of the power supply.

s-

K2

Ki

42V

F1

R6 350V

EMS

1A6T

R7 350V

ISM1%

C8

1% 470n630V 4x 1N4007

D1 D3

D2 D4

C9 Re1

r1 =I.7.=1000p

24V 35V

D5

131T1

BC560C

CiR3 R5

Ri 117

1117BC:OC

R8 R9 R10

Tr1

Re1 = V23056 -A105 -A101

4

22n

C7

22n

15V3VA3

B80C1500

42V

15MIM

22n

C6

72n

R13

R11

IC1

7815015V

C3D7

C2-I. NM

770p 100n40V

R120 EEE

D6

15V

C1O25V00

015V

The voltage is used to compensate thebase currents of the input stage via R55and R74 to such a degree that the directvoltage at the basis is virtually nil. Inte-grator IC3 removes any residual directvoltage (caused by, for instance, temper-ature changes). Its output is used to ad-just the base voltage of T1 and T3 viaR53 -C21, R54 and R73.

Protection circuitThe protection circuit, whose diagram isshown in Fig. 2, serves a number of func-tions.Switch -on click. When the power is switchedon, C3 is charged slowly via R4. After ashort while, darlington T7 -T8 comes on,whereupon the LEDs in the optoisolatorsbegin to conduct gradually. When the po-tential across C3 has risen to 1.7-1.8 V,the diodes light brightly. This situationremains because D5 holds the base volt-age of T7 at a fixed level.Switch -off click. As long as the mains isswitched on, T1 conducts every half pe-riod (since it is connected directly to thesecondary of the mains transformer viaD1 and D2), whereas T2 and T3 are off.When the mains is switched off, T2 andT3 are switched on within half a period.Schmitt trigger T4 -T6 changes state, where-upon T5 conducts and T7 and T8 are cutoff, so that the optoisolators are deactu-ated. This state is indicated by the light-ing of D11.Over -current. Current monitor T22 in theamplifier is linked to terminal A via theauxiliary circuit (Fig. 5). If the output cur-rent of the amplifier rises unduly, T3 switcheson, whereupon the optoisolators are de -actuated as described earlier. At the sametime, triacs Trii and Trig are switched onby T11 via D8 and short-circuit the supplylines. If this drastic action is not accept-able, D8 may be omitted.Temperature. Transistor T12 functionsas a temperature sensor diode which ismounted on the heat sink of T14 -T21. Thevoltage across the transistor is comparedby ICI, with a preset (P1) reference volt-age. If the sensor voltage drops (temper-ature rises) below the reference potential,ICI, changes state and the optoisolatorsare deactuated via D6. Once the temper-ature has dropped below a safe value, theamplifier is switched on again.Direct voltage. If there is a direct volt-age greater than ±0.6 V at the output ofthe amplifier (point D), either T9 or T10 isswitched on via low-pass section R23 -C8.In either case, the negative input of ICI],is pulled to earth and its output changesfrom low to high. This results in the tri-acs being switched on via D9 and T11. Atthe same time, D7 causes the Schmitt trig-ger to change state, resulting in the op-toisolators being deactuated. This func-tion may be disabled by omitting D7 andDg.

930039 - 14 -

Fig. 5. Diagram of the auxiliary circuit.ELEKTOR ELECTRONICS MARCH 1994

100 W HIGH -END POWER AMPLIFIER 19

Fig. 6. Printed circuit board for the auxiliary circuit (scale 1:1).

Power supply

The power supply for the amplifier (seeFig. 4) is a traditional design. A double -pole mains switch and switch -on delaycircuit are followed by the usual combi-nation of transformer, bridge rectifier andelectrolytic smoothing, buffer and reser-voir capacitors. The series resistors limitthe peaks in the charging currents of theelectrolytic capacitors and, together withthese capacitors, form an effective mainsfilter.

Auxiliary circuitThe auxiliary circuit (see Fig. 5) consistsof a ±15 V supply and a mains on delay.

The ±15 V supply is provided by Tr 1,Bland various capacitors. The +15 V lineis stabilized by a Type 7815 regulator,

vl

I S

but the -15 V line by a simple zener diode,D6, since that line is further stabilized inthe amplifier by a Type LM337 regulator(IC4). Mains on indication is provided byR13 and D7.

The section based on T1 and T2 acts asa monitor for the current protection. It isinserted between amplifier output A andterminal A on the protection board. Thecircuit transforms the potential measuredby current sensor T22 into a much lowervoltage (relative to earth) suitable for theprotection circuit.

The design of the mains on delay cir-cuit between K1 and K2 is straightforward.As soon as the mains at K1 is switched

'NVF ,S

SZ$oalt). °CIS>

!li=b 0alao-ne

on, the amplifier is powered immediatelyvia K2, but the current to it is limited se-verely by R8 -R11. This means that the elec-trolytic capacitors in the main powersupply are charged relatively slowly andthat the mains fuse does not have to copewith a substantial surge. Within a shortwhile, C9 is charged via R6, C8 and D1 -D4to such an extent that the potential acrossit is sufficient to energize relay Rel. Parallel -connected resistors R8 -R11 are then short-circuited by the relay contact and fullpower is applied to the amplifier.

Diode D5 limits the voltage across C9while R7 ensures that 'a. c. resistor' C8 is

otsto.

T. c.0110TA"DHP'q! n/irsaavro

a

11:8cr,,o

4 Pc'ai(N

-171!lit 01:30. Ms F2

=

C12

5_1

Fig. 7. Component layout of the PCB forthe protection circuit (scale 1:2).


Fig. 8. Component layout (scale 1:2) of the PCB for theamplifier (one channel).

20 AUDIO

PARTS LIST (ONE CHANNEL)

AUXILIARY CIRCUIT

Resistors:R1; R2; R4 = 1 kS2R3; R5 = 10 k4R6 = 220 S2 1 W; e.g., PRO1 (Philips)R7 = 1 MO, 350 V; e.g., SFR25H(Philips)R8-1211 = 180 D, 5WR12 = 2.2 kD, 1 W; e.g., PRO1R13 = 8.2 kt-2

Capacitors:C1 = 10 µF, 25 V radialC2 = 100 nF ceramicC3 = 470 µF, 40 V, radialC4 -C7 = 22 nF, ceramicC8 = 470 nF, 630 VCg = 1000 µF, 35 V, radial

Semiconductors:B1 = B80C1500D1 -D4 = 1N4007D5 = 24 V, 1.4WD6 = 15 V. 0.4 WD7 = LED green, low currentT1 = BC560CT2 = BC550C

Integrated circuits:ICI = 7815

Miscellaneous:K1; K2 = 2 -way PCB terminal block,

pitch 7.5 mmTr1 = 15 V, 3.3 VA, e.g., VTR3115

(Monacor/Monarch)Ref = V23056 -A105 -A101 (Siemens)F1 = 1A6 T w. PCB holder

PROTECTION BOARDResistors:R1 = 82 kS2R2 = 1 MDR3; R7; Rg; R25; R26 = 100 k4R4 = 15 kS2R5 = 100 t2R6; R22 = 1 k4R8 = 47R10 = 1.5 MDR11 = 3.9 MDR12: R13 - 56 kDR14; R27 = 4.7 k4R15= 104R16; R17 = 390 D,R18= 15R19 = 3.3 Ict-2R20 = 180 k4R21 = 22 MDR23 = 10 Ic4R24 = 220 kS2R28; R29 = 22012, 1 WR30 -R33 = 1.2 D, 5 WP1 = 50 kQ preset H

1W

Capacitors:C1 = 220 µF, 25 VC2; C7 = 100 nFC3 = 470 µ F, 6.3 VC4= 1 aFC5 = 10 a F, 10 V, radial

C6 = 220 µF, 16VC8 = 100µF, 10 V, radial, bipolarCg = 39 nFC10 = 220 nF

Semiconductors:D1,D2 = 1N4004D3 = 1N4001D4 = 5.6V, 0.4 WD5 = LED greenD6 -D9 = 1N4148 (fit w. connectors on

PCB pins)D10 = LED orangeD11 = LED, red, high efficiencyTi; T2; T4; T10 = BC547BT3 = BC516T5; T6; T7 = BC557BT8 = BD 140 + heatsinkT9 = BC547AT11 = BD679

Integrated circuits:ICI = CA3240IC2 = 7805

Miscellaneous:Trii;Tri2 = TIC263M3 off screw -mount spade terminal for

PCB mounting1 off PCB Ref. 920135-2 (see page 70)

AMPLIFIER BOARDResistors:RI; R34; R35; R75 = 562 D, 1%R2; R76 = 47.5 MI, 1%R3; R4; R8; Rg = 2.49 k4, 1%R5; R10 = 10 52R6; R7; R11; R12 = 24.9 D, 1%R13; R14 = 249 D, 1%R15 = 820R16 = 18.2 MI, 1%R17; R18 = 4.71d2

R19; R20; R23; R24 = 187 D, 1%R21; R22; R25: R26 = 18.714 1%R27 = 133 t2, 1%R28: R29 = 390R30; R31 = 23.2 D. 1%R32 = 470 t2R33; R44 = 330 t2R36 -R39; R50 = 56.2 D, 1%

R42: R43; R61; R62; R64; R65; R66; R69= 0.22 D, 5 W, low -inductance

R40; R41; R60; R63; R67; R68; R70:R71= not used

R45= 180DR46 = 4-7 kQR47 = 4.7 52, 5WR48; R51 = 100 4R49 = 1.47 k4, 1%R52; R53; R72 = 56 k4R54 = 12 MDR55; R74 = 1.8 MDR56 = 270R57 = 1 ki2R58; R59 = 8.2 k4R73 = 18 MDRL (in L1) = 2.2 D, 5 WPI = 500 D multiturn, vertical preset

(Bourns 3296Y)P2 = 2 kD multiturn, vertical preset

(Bourns 3296Y)

Capacitors:C1; C23 = 2.2 µF, 50 V, MKTC2 = 820 pF, polystyreneC3, C4 = 1.5 nFC5 -C8 = 47 µF, 10VCg; C10 = 560 pF, polystyreneC11; C20; C21 - 1 FC12 = 100 nFC13 = 5.6 nFC14 -C17 = 10 000 9F, 50 V, radial, for

PCB mountingC18; C19 = 1000 µF, 25 V, radialC22 -10 0', 25 VC24 = 4.7 nFC11, = 220 pF, polystyrene (mount at

track side)

Semiconductors:D1 -D4 = LED, red (VF= 1.6 V)D5 = LED, red (high efficiency)D6 = LED, green (high efficiency)D7; D8 = 1N4148Dg; D10 = not usedT1; T2 = 2N2914T3; T4 = BFX36T5 = BC560CT6 = BC550CT7 = BC141-16T8 = BC161-16Tg = BF256CT10; T11 = BF256A (interconnect gate

and source; cut off gate)T12; T17 = MJE15031T13; T16 = MJE15030T14; T15 = BD 139T18; T19 = 2SC2922 (Toshiba)T20; T21 = 2SA1216 (Toshiba)T22 = BF869 (interchange base and

collector)

Integrated circuits:ICI4C2 = 4N35IC3 = OP77IC4 = LM337

Miscellaneous:L1 = 10 turns (15 mm dia.) of 1.5 mm

dia. enamelled copper wireK1 = phono socket for PCB mounting

(or two PCB pins).F1;F2 = 6.3 A (with fuseholder).5 off spade terminal, screw type.1 off heat sink max. 0.5 K W-1.2 off heat sink for T12 and T131 off PCB Ref. 920135-1 (see page 70)

POWER SUPPLY & ENCLOSURETr1 = ring core transformer, sec. 2x30V,

300 VA, e.g., 71017 (Amplimo or ILP)B1 = B200C35000 (200 V/35 A bridge)R1 -R8 = 0.1 II, 5 WC1 -C4 = 10 000µ F, 50 V1 off mains socket1 off mains switch2 off phono socket (gold-plated)2 off loudspeaker terminal or banana

socketEnclosure : e.g., ESM Type ET38/13

(300 mm deep) (Maplin)


100 W HIGH -END POWER AMPLIFIER

discharged rapidly when the supply isswitched off.

ConstructionThe printed -circuit board for the auxil-iary circuit is shown in Fig. 6, and thecomponent layout of the PCB for the pro-tection circuit and the amplifier in Fig. 7and Fig. 8 respectively. The latter twowere shown full-scale in Ref. 2 and Ref. 1respectively. There is no board for thepower supply of Fig. 5, so this must be

constructed on a prototyping board. ThePCBs are available ready made throughour Readers' Services.

Building the auxiliary circuit is straight-forward and consists merely of populat-ing the board with reference toFig. 6 andthe parts list.

The same applies to the protection cir-cuit. Do not forget the heat sink for T8and use heavy duty terminals for the con-nections to the triacs.

As far as the amplifier board is con-cerned, a full description was given in

Ref. 2, which includes a template for dril-ling the heat sink. The following descrip-tion will concentrate on the more impor-tant details only and on the aspects re-sulting from the modifications in the pre-sent amplifier over that in Ref. 2.

Mount most of the components on theboard, but, for convenience's sake, leavethe large electrolytic capacitors till a lit-tle later. Although different types of dualtransistor are used in the T1 -T4 positions,they are also housed in a TO -78 enclos-ure and they are pin -compatible with the

AUDIO

1

01

0 010

0 001

0005

RECISION DEFAULT THD+N(%) vs FREO Hz) 18 NOV 9312:09:23 I AUDIO PRECISION THDVSLVL THD+N % vs measured LEVEL(W) 18 NOV 9312:24:48

1...m...4

A p fiMEMIEE=mamilliME=Mgrai PMI= MIMI I

,I

I

ll Ell 0.1

I

MalliM. MC=H

1.1111MMEI= 011.=mm . IIM ,

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-IIi

Ill . I

0.001 .. ,. ..'ii==MO

(inns

20 100 1k 10k 20k 10m 0.1 10 100 200

AU

Characteristic A

)10 PRECISION PWR-BAND LEVEL(W) vs FREO(Hz) 18 NOV 9313:09:19

500A p

100

10

.

20 100 1k 10k 20k

Characteristic C

The results of the measurements on theprototype are, without exception. verygood. Noise and residual distortion arefar removed from the human limits ofobservation. Pulse response and damp-ing factor are almost ideal, although thatis a strong word to use.

Listening tests confirm the measuredvalues, Even the most demanding record-ings from our record library were repro-duced without any discernible hitch.

The four characteristics shown above.

Characteristic B

Elektor

0.0

-20.00

-40.00

-60.00

-80.00

.100.0

.120.0

-140.0

-160.0

0.0

GB2FFT AMP1(dBr) vs FREO Hz) 18 NOV 9311:27:22

A p

1

500.0 1-00k 1.50k 2.00k 250k 300k 350k 400k

obtained with an Audio Precision Analyser,illustrate these statements.

Characteristic A shows the totalharmonic distortion plus noise (THD +N) over the frequency range 20 Hz to20 kHz at an output power of 50 W.

Characteristic B illustrates the dis-tortion at 1 kHz as a function of the drivelevel over the frequency range 22 Hz to22 kHz. It is clear that between 10 W and20 W the limits of the analyser were reached.The sharp bend at the nght-hand side

Characteristic D

of the curve is the clipping point.Characteristic C shows the maxi-

mum power at a distortion of 0.1%; itwill be seen that within the audio rangethe power is completely independent offrequency

Characteristic D gives the Fourieranalysis of a 1 kHz signal at an outputof 1 W into 8 CI with the fundamental fre-quency suppressed. The attenuation ofthe 2nd harmonic is about 125 dB, whilethe 3rd harmonic is lost in the noise.

Box 2. Four characteristics illustrating certain measurements on the prototype amplifier.


AUDIO & HI -Fl

earlier types. The types of transistor usedin the T7 and T8 positions are also pin -com-patible with the earlier types, but theyare slightly larger, which adds to the den-sity on the board.

Field-effect transistors T10 and T11 needto be modified slightly before they can befitted. Since their gate must not be con-nected to the board, the relevant pin mustbe linked to the source pin and as muchof it cut off as possible. The result is aFET with only two pins which are to beinserted in the holes intended for the drain

and source.Since the board was originally intended

for a BC550C, the collector pin of T22 (aBF869) must be inserted into the holeoriginally meant for the base, and the basepin into the original commector hole. Takecare not to short-circuit these pins.

The same sort of thing needs to be donewith T12 and T13. Since the types now usedare housed in a TO -220 case, they mustbe mounted on the board the wrong wayaround, that is, with the metal plane atthe inside.

Resistor RL must be mounted centrallyinside air -cored inductor L1. The coil con-sists of 10 turns of 1.5 mm diameter enam-lled copper wire wound on a 15 mm di-ameter tube. Make small loops at the endsof the wire so that the coil can be mountedon the board with small bolts and nuts.

There are no holes provided for Cfb:this capacitor should be soldered at thetrack side of the board directly across R49.

Diodes D9 and D10 must not be usedin the present amplifier. Fit PCB pins inthe holes intended for these diodes and

K1

LS1 11111111111111111111

Tr1

B1

- ti

0 0-1-F.'"-=,-""---\

FCII

7!M :3

c4=0 (piowp 00E.

= YrdI

.101,

*1 6=6 0 0

cima,

4 LE "2

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1.2111141

cmooilgoili:Ic ak

S 316

IM

>=. ° " "'

sa

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irlg3C0,0110-auJL

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gelsoleeMop koelplaat

ERROR

N

930039 - 16

Fig. 9. Wiring diagram for the amplifier (one channel).


100 W HIGH -END POWER AMPLIFIER

link them to the ±15 V supply on the aux-iliary circuit board.

Since sense lines to the loudspeaker(s)are no longer used, terminal FB2 mustbe linked to the junction L1 -R47, and FB1to the earth terminal of the loudspeaker(clamp together with the loudspeakercable in the spring -loaded terminal).

If car -type fuses of 6.3 A are unob-tainable, use a glass fuse mounted in atraditional holder soldered on to the screwtype terminals.

Use flat car -type connectors for ter-minating the supply lines and also for theoutput lines (these come at the under-side of the board).

The board is intended to form a (lat-eral) 'T' with the heat sink. Screw thepower transistors and T14 -T17, mountedon the amplifier board, to the heat sink:use insulating washers in all cases. Donot yet fit T12 to the upper half of the heatsink: see under `Alignment'.

A completed single -channel amplifiermodule is shown in Fig. 10. Its wiring di-agram is given in Fig. 9. Use heavy-dutywire (4mm2 cross-section) for the powerlines, output lines to the loudspeaker(s)and the lines between the amplifier boardand the triacs on the protection board.Use screened cable for the input lines.Such cable is also recommended to linkpoints A on the three boards.

It proved impossible to obtain an en-closure suitable for housing two ampli-fier modules to form an integrated stereoamplifier; the prototype stereo amplifiertherefore consists of two individual monoamplifier modules.

AlignmentSet P1 to maximum resistance: checkthis with an ohmmeter. Switch on themains, and measure the voltage at thevarious points shown in Fig. 2 and Fig. 3.If these are all as specified, measure thevoltage across one of the emitter resistorsof T18 -T21 with a digital voltmeter andadjust P1 until the meter reads 22 mV(which corresponds to a quiescent cur-rent of 200 mA per transistor).

Next, again with a digital voltmeter,measure the direct voltage at the base ofT1 or T3; adjust P2 to make the readingexactly zero.

Then, measure the output voltage ofIC4, which must be between 0 V and -11 V.If the voltage is more negative, reduce thevalues of R55 and R74 by about 10% (afterswitching off the amplifier!).

Next, check the output voltage of IC3(pin 1). After the amplifier has been switchedon for a little while, this voltage shouldremain within ± 10 V. If this is not thecase, reduce R73 to the next lower E12value.

Finally, connect T12 via a short lengthof cable to terminals C and earth on theprotection board. Place the transistor ina dish of warm water (about 60 °C), mak-ing sure that the device's terminals are

not short-circuited by the water. Adjust References:P1 on the protection board until D10 on 1. 'Medium power a.f. amplifier', Elektorthe same board just lights. Then, fit T12 Electronics, October/November 1990to the heat sink. Bear in mind that thetemperature of the heat sink even in normal 2. 'Output amplifier for ribbon loudspeakers',operation becomes at least 20 °C higher Elektor Electronics, November/Decemberthan ambient. END 1992.

Fig. 10. Completed single -channel (mono) amplifier module.

11.,e4r'''

Fig. 11. Mono amplifier module seen from top with cover of enclosure removed.


24Please mention ELEKTOR ELECTRONICS when contacting advertisers

Surplus alwayswanted for cash! THE ORIGINAL SURPLUS WONDERLAND! Surplus always

wanted for cash!

LOW COST PC SPECIALISTS - ALL EXPANDABLE - ALL PC COMPATIBLE8088 XT - PC99

ottiiik' I -

,6;Neato6tulitaii,

256k RAM - expandableto 640k

4.7 Mhz speed 360k 5-1/4" floppy 2 serial & 1 parallel ports MS-DOS 4.01

Factory burnt -in Standard 84 key

keyboard 12" green screen

included In good used condition

Optional FITTED extras: 640K RAM £39. 12" CGA colourmonitor with card £39. 2nd 5-1/4" 360K floppy £29.95. 20mbyte M FM hard drive £99.

oniy£99.00(F)

FLOPPY DISK DRIVES51/4 " from £22.95 - 31/2" from £21.95!

Massive purchases of standard 51/4" and 31/2" drives enables usto present prime product at industry beating low prices! All units(unless stated) are removed from often brand new equipmentand are fully tested, aligned and shipped to you with a 90 dayguarantee and operate from standard voltages and are of stand-ard size. All are IBM-PC compatible (if 31/2" supported).3.5" Panasonic JU363/4 720K or equivalent £29.95(B(3.5" Mitsubishi MF355C-L. 1.4 Meg. Laptops only' £29.95(B)3.5" Mitsubishi MF355C-D. 1.4 Meg. Non laptop £29.95(B(5.25" EXTRA SPECIAL BRAND NEW Mitsubishi MF50113

360K. Absolutely standard fits most computers £22.95(B)* Data cable included in price.

Shugart 800/801 SS refurbished & tested £175.00(E)Shugart 851 double sided refurbished & tested £275.00(E(Mitsubishi M2894-63 double sided switchable

hard or soft sectors- BRAND NEW £250.00(E)Dual 8" drives with 2 mbyte capacity housed in a smart casewith built in power supply! Ideal as exterior drives! £499.00(F)End of line purchase scoop! Brand new NEC D2246 8" 85megabyte of hard disk storage! Full CPU control and industrystandard SMD interface. Ultra hi speed transfer and access timeleaves the good old ST506 interface standing. In mint conditionand comes complete with manual. Onl £299(E)

THE AMAZING TELEBOX!Converts your colour monitor into a

QUALITY COLOUR TV!!

TV SOUND& VIDEOTUNER!

The TELEBOX consists of an attractive fully cased mainspowered unit, containing all electronics ready to plug into a hostof video monitors made by manufacturers such asMICROVIT EC, ATARI, SANYO, SONY, COMMODORE,PHILIPS, TATUNG, AMSTRAD and many more. The compositevideo output will also plug directly into most video recorders,allowing reception of TV channels not normally receivable onmost television receivers (TELEBOX MB). Push button controlson the front panel allow reception of 8 fully tuneable 'off air' UHFcolour television or video channels. TELEBOX MB covers vir-tually all television frequencies VHF and UHF including theHYPERBAND as used by most cable TV operators. Compositeand RGB video outputs are located on the rear panel for directconnection to most makes of monitor. For complete compatibility- even for monitors without sound - an integral 4 watt audioamplifier and low level Hi Fi audio output are provided asstandard.Telebox STTelebox STLTelebox MB

for composite video input monitors £32.95as ST but with integral speaker £36.50as ST with Multiband tuner VHF -UHF -Cable.& hyperband For overseas PAL versions state5.5 or 6mhz sound specification. £69.95

Telebox RGB for analogue RGB monitors (15khz) £69.95Shipping code on all Teleboxes is (B)

RGB Telebox also suitable for IBM multisync monitors with RGBanalog and composite sync. Overseas versions VHF & UHF call.

SECAM / NTSC not available.

No Break Uninterruptable PSU'sBrand new and boxed 230 volts uninterruptable power suppliesfrom Densei. Model MUK 0565-AUAF is 0.5 kva and MUD1085-AHBH is 1 kva. Both have sealed lead acid batteries. MUKare internal, MUD has them in a matching case. Times frominterrupt are 5 and 15 minutes respectively. Complete with fulloperation manuals MUK £249 (F) MUD £525 (G)

286 AT - PC286

640k RAM expandablewith standard SIMMS

12 Mhz Landmark speed 20 meg hard disk 1.2 meg 5-1/4" floppy 1.4 meg 3-1/2" floppy EGA driver on board

2 serial & 1 parallelports

MS-DOS 4.01 Co -processor socket Enhanced 102 key

keyboard Clock & calendar with

battery back upBRAND NEW AND BOXED!

oniYE249.00The Philips 9CM073 is suggested for the PC286 and theCM8873 for the PC386. Either may use the SVGA MTS-9600if a suitable card is installed. We can fit this at a cost of £49.00for the PC286 and £39.00 for the PC386.

POWER SUPPLIESPower One SPL200-5200P 200 watt (250 w peak).Semi openframe giving +5v 35a, -5v 1.5a, +12v 4a (8a peak), -12v 1.5a,+24v 4a (6a peak). All outputs fully regulated with over voltageprotection on the +5v output. AC input selectable for 110/240vac. Dims13" x 5" x 2.5". Fully guaranteed RFE. £85.00 (B)

Power One SPL130. 130 watts. Selectable for 12v (4A) or 24 v(2A). 5v @ 20A. ± 12v CI 1.5A. Switch mode. New. £59.95)B)Astec AC -8151 40 watts. Switch mode. +5v @ 2.5a. +12v @2a. -12v @ 0.1a. 6-1/4" x 4" x 1-3/4".New £22.95(B)Greendale 19ABOE 60 watts switch mode.+5v @ 6a,±12v1a,+15v @ 1 a. RFE and fully tested.11 x 20 x5.5cms. £24.95(C)Conver AC130. 130 watt hi -grade VDE spec.Switch mode.+5v

15a, -5v C4 1a,±12v ft 6a.27 x 12.5 x 6.5cms.New. £49.95(C)Boshert 13090.Switch mode.ldeal for drives & system. +5v @ 6a,+12v @ 2.5a, -12v (4 0.5a, -5v ft 0.5a. £29.95(B)Farnell G6/40A. Switch mode. 5v @ 40a.Encased £95.00(C)Farnell G24/5S. As above but 24v ft 5a. £65.00(C)

BBC Model B APM Board£100 CASH FOR THE

MOST NOVELDEMONSTRATABLE

APPLICATION!BBC Model B type computer on a board. A major purchaseallows us to offer you the PROFESSIONAL version of the BBCcomputer at a parts only price. Used as a front end graphicssystem on large networked systems the architecture of the BBCboard has so many similarities to the regular BBC model B thatwe are sure that with a bit of experimentation and ingenuity manyuseful applications will be found for this board!! It is suppliedcomplete with a connector panel which brings all the I/O to 'D'and BNC type connectors - all you have to do is provide +5 and± 12 v DC. The APM consists of a single PCB with most majoric's socketed. The ic's are too numerous to list but include a6502, RAM and an SAA5050 teletext chip. Three 27128EPROMS contain the custom operating system on which wehave no data, On application of DC power the system boots andprovides diagnostic information on the video output. On boardDIP switches and jumpers select the ECONET address andenable the four extra EPROM sockets for user software. Appx.dims: main board 13" x 10". I/O board 14" x 3". Supplied testedwith circuit diagram, data and competition entry form.

Only £29.95 or 2 for £53 (B)SPECIAL INTEREST

Trio 0-18 vdc bench PSU. 30 amps. NewFujitsu M3041 600 LPM band printerDEC LS/02 CPU boardRhode & Schwarz SBUF TV test transmitter

25-1000mhz. Complete with SBTF2 ModulatorCalcomp 1036 large drum 3 pen plotterThurlby LA 160B logic analyser £ 3751.5kw 115v 60hz power source £ 950Anton Pillar 400 Hz 3 phase frequency converter 75Kw POANewton Derby 400 Hz 70 Kw converter POANikon PL -2 Projection lens meter/scope £750Sekonic SD 150H 18 channel Hybrid recorder £2000HP 7580A A1 8 pen high speed drum plotter £1850Kenwood DA -3501 CD tester, laser pickup simulator £ 350

£ 470£2950£ 150

£6500£ 650

BRAND NEW PRINTERSMicroline 183. NLQ 17x17 dot matrix. Full width. £139 (D)Hyundai HDP-920. NLQ 24x18 dot matrix full width. £149 (D)Qume LetterPro 20 daisy. Qume QS -3 interface. £39.95 (D)Centronics 152-2 9 x 7 dot matrix. Full width. £149 (D)Centronics 159-4 9 x 7 dot matrix.Serial. 9-1/2" width £ 99 (D)

1992 Winter Issue of Display News .000. :OM% : WOO Me

000

000 .0...

.

I I

386 AT - PC386

I

2 meg RAM expandedby slots

20 Mhz with 32k cache.Expandable to 64k

40 meg hard disk 1.2 meg 5-1/4" floppy VGA card installed

2 serial & 1 parallelports

MS-DOS 4.01 Co -processor socket Enhanced 102 keyboard Kwik Disk Accelerator

Software - FREEBRAND NEW AND BOXED!

only£425.0a,MONITORS

14" Forefront Model MTS-9600 SVGAmultisync with resolution of 1024 x 768.0.28pitch. "Text" switch for word processing etc.Overscan switch included. Ideal for the PC -386 or PC -286 with SVGA card added. Alsocompatibe with BBC, Amiga, Atari (includingthe monochrome high resolution mode), Ar-

chimedes etc. In good used condition (possible minor screenburns). 90 day guarantee. 15" x 14" x 12" Only £159(E)

14" Philips Model CM8873 VGA multisyncwith 640 x 480 resolution. CGA, EGA orVGA, digital/analog, switch selectable.Sound with volume control. There is also aspecial "Text" switch for word processing,spreadsheets and the like. Compatible withIBM PC's, Amiga, Atari (excluding themonochrome high resolution mode), BBC,

Archimedes etc. Good used condition (possible minor screenburns) 90 day guarantee. 15" x 14" x 12". Only £139(E)Philips 9CM073 similar (not identical) to above for EGA/CGAPC and compats. 640 x 350 resolution. With Text switch withamber or green screen selection. 14" x 12" x 13-1/2" ...£99(E)KME 10" high definition colour monitors. Nicetight 0.28" dot pitch for superb clarity and'modern styling. Operates from any 15.625 khzsync RGB video source, with RGB analog andcomposite sync such as Atari, CommodoreAmiga, Acorn Archimedes & BBC. Measuresonly 13.5" x 12" x 11'. Also works as quality Tv witn our HudTelebox. Good used condition. 90 day guarantee. Only £125 (E)KME as above for PC EGA standard £145 (E)Brand new Centronic 14" monitor for IBM PC and compatiblesat a lower than ever price! Completely CGA equivalent. Hi-resMitsubishi 0.42 dot pitch giving 669 x 507 pixels. Big 28 Mhzbandwidth. A super monitor in attractive style moulded case.Full90 day guarantee. OnlyNEC CGA 12" IBM-PC compatible. High

£129(E)

quality ex -equipment fully tested with a 90 -day guarantee. In an attractive two toneribbed grey plastic case measuring 15"L x13"W x 12"H. The front cosmetic bezel hasbeen removed for contractual£69

(E)reasons. Only ......20", 22" and 26" AV SPECIALS

Superbly made UK manufacture. PIL all solid state colourmonitors, complete with composite video & sound inputs. Attrac-tive teak style case. Perfect for Schools,Shops,Disco, Clubs.In EXCELLENT little used condition with full 90 day guarantee.

20"....£135 22"....£155 26"....£185 (F)CALL FOR PRICING ON NTSC VERSIONS!

Superb Quality 6 foot 40u

19" Rack CabinetsMassive Reductions

Virtually New, Ultra Smart!Less Than Half Price!

Top quality 19" rack cabinets made in UKby Optima Enclosures Ltd. Units featuredesigner, smoked acrylic lockable frontdoor, full height lockable half louvered backdoor and removable side panels. Fully ad-justable internal fixing struts, ready

punched for any configuration of equipment mounting plus readymounted integral 12 way 13 amp socket switched mains distribu-tion strip make these racks some of the most versatile we haveever sold. Racks may be stacked side by side and thereforerequire only two side panels or stand singly. Overall dimensionsare 77-1/2"H x 32-1/2"D x 22"W. Order as:Rack 1 Complete with removable side panels.. ..... £275.00 (G)Rack 2 Less side panels £145.00 (G)

now available - send large SAE - PECKED with bargains!MO O.

e. II

0 0.990 90

$ 00

All prices for UK Mainland. UK customers add t7.5% VAT to TOTAL order amount. Minimum order £10. PO orders from Government,Universities,Schoots & Local Autho 'tieswelcome -minimum account order £30. Carnage charges (A)=£2.00. (Al )=£3.75. (B)=£5.50. (C)=£8.50. (0).£11.50. (E)=£14.00 (F)=C18.00 (G)=Call . Scotland surcharge: call.All goods supplied subject to our standard Conditions of Sale and unless otherwise stated guaranteed for 90 days. At guarantees on a retum to base basis.Rights reserved tochange prices & specifications without prior notice. Orders subject to stock. Quotations willingly given for higher quantities than those stated. Bulk surplus always wanted forcash.

-

I ; '

I: . . I.r


Please mention ELEKTOR ELECTRONICS when contacting advertisers

ESR ELECTRONIC COMPONENTSStation Road, Cullercoats, DEPT. EETyne & Wear NE30 4PQTel. 091 251 4363 Fax. 091 252 2296

74LS-Series741500741S0174150274150374150474150574100874150974LS1074101077415109741511741S1127415113741511474151274151227410123741S125741S1267415137410132741_01337415136741_31387415139741_51474151457415147741014874101574131517415153741S154741_5155741515674101577413158741016074L5161741_0162741_0163741_516474LS16574[S1707410173741517474151757415190741_0191741019274L5193741S195741_4196741_0197741520741521741_5227410221741S240741_324174LS24274[S24374[S2447410245741524774LS25174[S2577410258741526741_0266741_0277415273741_5279741530741532741536574LS36774LS36874[S3774103737410374741_5375741537774[S378741_538741S39074153937410395741_539974154074LS4274LS4774[S51741_5670741_573741_574741_57574[S7674L58374158574158674109074LS9274LS93

£0.14£0.14£0.14£0.14£0.14£0.14£0.14£0.14£0.14£0.23£0.21

£0.17£0.21

£0.21£0.21

£0.14£0.31

£0.31£0.21

£0.21£0.14£0.21

£0.18£0.16£0.24£0.25£0.18£0.560 .26£0.70£0.14£0.25£0.25£0.70£0.25£0.36£0.25£0.25£0.32£0.32£0.32£0.32£0.26£0.443

£0.30£0.24£0.24£0.24£0.25£0.24f 0.42£0.24£0.24£0.24£0.24£0.16£0.14£0.14£0.36£0.32£0.32£0.32£0.32£0.32£0.33£0.32£0.24£0.24£0.24£0.14£0.14£0.14£0.32£0.25£0.14£0.14£0.21£0.21£0.21

£0.14£0.32£0. 32

£0.34£0.32£0.62£0.14£0.25£0.24£0.26£0.62£0.14£0.25

£L1.14

£0.69£0.17

£0.19£0.25£0.31

£0.35£0.20£0.23£0.35£0.25

ENAMELLEDCOPPER

WIRE

All 2oz Reels14 SWG £0.6316 SWG £0.6718 SWG £0.6720 SWG22 SWG24 SWG26 SWG28 SWG30 SWG32 SWG34 SWG36 SWG38 SWG40 SWG

£0.72£0.76£0.80£0.89£0.91£0.93£0.93£0.99£1.04£1.10£1.22

4000 Series4000400140024006400740084009401040114012401340144015401640174018401940204021402240234024402540264027402840294030403140334034403540404041404240434044404640474048404940504051405240534054405540E740634066406740684069407040714072407340754076407740814082408540864089409340944095409740984099450245034508451045114512451445154516451845204521452645274528452945324534453845384541454345554556456045684572458445854724401064010940163401744017540193

£0.1700.21£0.17£0.32£0.17£0.31£0.190.23£0,16£0.16£0.21£0.30£0.31£0.18[0.27£0.27£0.19£0.31£0.31£0.32£0.16£0.21£0.15L0.59£0.18£0.22£0.36£0.17£0.70£0.56£1.24£0.31£0.29£0.31£0.22£0.28(0.35£0.31£0.25£0.31£0.20£0.20E0.36£0.25£0.25£0.56L0.34

£0.29£0.18£1.91£0.16£0.20£0.17£0.20£0.17£0.17£0.17£0.30£0.17£0.14£0.17£0.28£0.26£0.55L0.18£0.31£0.56£1.20

£0.38£0.38£0.31£0.90£0.26[0.32[0.3200.77[0.98£0.31£0.27£0.26£0.62£0.40£0.39£0.40£0.44£0.32£2.48£1.00£0.37[0.33£0.46£0.34£0.34f1.18£1.96£0.25£0.24£0.32£0.70£0.31£0.50£0.46£0.34£0.36£0.60

TRANSISTORS2N16132N1711251E193252218A252219A2N2222A2N26462N2904A2N2905A2N29072N29262N30532N30542N30552534402537022537032N37042N37052N37062N37712537722537732538192N38202539042N39052539062N4036255296255321256107AC126AC127AC128AC187AC188ACY17AD149AD161AD162BC107BC107B5C108BC108ABC108CBC109BC109CBC114BC1158C116BC118BC132BC134BC135BC140BC141BC142BC143BC149BC154BC157BC159BC160BC170BCI 70BBC171BC171B5C172BC172BBC17713C178BC179BC182BC1821BC182LBBC183BC1831_BC1831BBC184BC184L

£0.31£0.26£0.29£0.28£0.25£0.16£0.80£0.25£0.23£0.20£0.16£0.27£0.90£0.62£0.50£0.09£0.10£0.10£0.10£0.10£1.44£1.51£1.79£0.40£0.58£0.10£0.10£0.10£0.31£0.57£0.57£0.60£0.30£0.30£0.28[0.45£0.37£3.84£1.67£0.92£0.92£0.14£0.15£0.13£0.14EJ ,6£0.14

£0.41£0.41£0.41£0.41£0.36£0.36£0.36£0.25£0.27£0.31£0.34£0.21£0.36£0.12£0.12£0.28£0.16£0.16£0.11£0.16£0.13£0.13£0.18£0.18£0.17£0.08£0.08£0.08£0.08£0.08£0.08£0.08£0.08

TRIACSZ0105DA £0.42TIC206D £0.65TIC226D £0.73131-A08-6008 E0.84TIC236D £0.96DIAC £0.20

VOLTAGEREGULATORS78L05781127811579L05791_1279L15780578127815790579127915LM3172LM723L200CVLM323KLM338K

£0.24£0.24£0.24£0.28£0.28£0.28£0.28£0.28£0.28£0.38e0.38£0.38£0.56£0.29f1.16£2.70£5.52

OPTO DEVICES5mrn Red LED5mm Green LED5mm Yellow LED5mm Orange LED3mm Red LED3mm Greer, LED3mm Yellow LED3mm Orange LED5mm Flashing Red5mm Flashing Green5mm Bi Colour5mm Tri Colour5mm Plastic Bezel3mm Plastic Bezel0 3" 7 Segment Display Redcommon anodecommon cathode

£0.09£0.10£0.10£0.10£0.08£0.12£0.13£0.13£0.50£0.54£0.36£0.48£0.04£0.05

£1.14£1.14

8C18613C204CBC20613BC207C134208BC209ABC212EIC212L.8C212LBBC213BC213LCBC214BC2141BC237B5C238CBC239CBC251BC252BC2616BC262BBC267BBC3075C308BC3278C328BC337BC338BC414CBC441BC461BC463BC478BC479BC490BC516BC5178C527BC528BC537BC546CBC547CBC548CBC549C1345504BC556ABC557C845584BC559CBC5608BC637BC638BC639BC640BCY70BCY71BCY728013500136801378013880139BD140BD150CBD16560166(313187402014020230203BD204BD222BD225002328023713023880240813024313BD244A0024680441130442

£0.33£0.72£0.72£0.72£0.72£0.72£0.08£0.08£0.08£008£008£0.08£0.08£0.09£0.09£0.10£0.13£0.13£0.24£0.24£0.30£0.10£0.10£0.10£0.10£0.10£0.10£0.13£0.40£0.40£0.29£0.32£0.32£0.24£0.220.20£0.20£0.20£0.20£0.08£0.09£0.08£0.10£0.08£0.08£0.08£0.08£0.08£0.09£0.21£0.21£0.21£0.21£0.21£0.20£0.20£0.20£0.21£0.22£0.22£0.23£0.24£0.82£0.42£0.35£0.39£0.40£0.40£0.40£0.40£0.40£0.42£0.38£0.32£0.32£0.37£0.50£0.53£106£0.41£0.41

0D5348D5355D5368D646BD648130650130707B D807BOX32808330BDX34CBDX53CBDX54CBF1808E182B F1858E1948E1958E244BF2578E259BF3378E35506423B F451B F4598E4698FX29BFX84BFX85BFY50BEY51B FY5255107BS170BSW6683126BU205BU208ABU326ABU500BU508ABU526131_1806

133884I RF5401RF740MJ11015MJ11016MJ2501MJ3001MJE340MJE350MPSA1 3MPSA42MRF475TIP121TIP122TIP125TIP127TIP132TIP137TIP1421161477162955211.29CTIP3055TIP3OCTIP31CTIP32CTIP33CTIP41ATIP42CTIP47TI P48TIP50VN1OKMVN66AFZTX300ZTX500

THYRISTORSP0102AATIC1060TIC116DTIC126D

£0.30£0.40£0.66£0.77

£0.47£0.48£0.65£0.52£0.52£0.53£0.42£0.80£1.78£0.46£0.50£0.47£0.50£0.31£0.31£0.31£0.19£0.19£0.35£0.33£0.33£0.36£0.38£0.13£0.19£0.29£0.36£0.29£0.31£0.31£0.29£0.26£0.28£0.21£0.21£1.35£1.70£1.82£1.73£1.80£2.32Cl .76£2.24£1.36£0.78£1.60£1.63£2.11£2.11£1 .60£1.52L0.40£0.42£0.120.17£6.21£0.35£0.37£0.37£0.37£0 46£0.46£1.08£1.12£0.63£0.31£0.63£0.31£0.32£0.320.72£0.36£0.38£0.48£0.62£0.53£0.44£1.50£0.16£0.16

HARDWARET2 Box 75 x 56 x 25mrn £0.82T3 Box 75 x 51 x 25mm £0.8274 Box 111 x 57 x 22mrn £0.98MB1 Box 79x 61 x 40nen £1.44M B2 Box 100 a 76 x 41mrn £1.56M83 Box 118 x 98 x 45rten £1.82M85 Box 150x 100 x 60mm £2.50

LINEAR ICsCA311ECA324CA555CA741 CECA747CECA3046CA3080CA3130453130ECA3140CA3240ICL7621ICM7555ICM7556LM301ALM348NLF351 NLF353LM358NL M377LM380NLM381[M386LM387LM3925LM393NLM748CNLM1458LM3900LM3914LM3915MC3340MC4558NE531NE556NNE567NNE5532NE5534TBA1205TBA810STBA820MTDA2030TL061TL062TL064TL071 CPTL072CPTL074CNTL0811_082CPTL084CNIJA7331/152004ZN4142Z5425E25426EZ9427525428EZN435EZN448E

£0.28EC 25£0.2222 2E£0.39£0.37£0.72£0.98£0.98£0.56£1.22£1.70£0.43£0.96£0.25£0.31£0.36£0.41£0.27£2.57£1.12£2.70£0.48£1.60E0.79£0.28£0.31£0.26£0.72£2.70£2.70£1.60£0.36£1.56£0.36£0.36£0.80£0.66£0.77£0.68£0.39£1.35£0.35£0.42£0.46£0.32£0.340.48£0.33£0.34£0.46£0.64£0.48£1 .04£4.68£2.61£8.82£6.12£5.31£7.92

EPROMS &RAMS

271627322764-2527C64 2521728-2027C128-2027256-2027C256-20

27C51227C0106116-106264.1062256-104164.1541256.10511000-8514256-8

L4.46£4.84£3.00[2.8043.6943.31£3.15[3.55

£3.6944.9741.53L3.06£4.8311.78[2.8045.61L5.61

DIL SOCKETS

8 Pin14 Pin16 Pin18 Pin20 Pin24 Pin28 Pin40 Pin

£0.07£0.11£0.15£0.15£0.16£0.19£0.22£0.25

ELECTROLYTIC RADIAL CAPACITORS

uF

0 47102247102247100220470100022004700

16V 25V

£0.05£005£0.06£0.06£0.09£0.15£0.22£0.37

£0.05£0.05£0.06£0.09£0.12£0.19£0.29£0.57£1 .11

63V£0.05£0.05£0.05£0.05£0.06£0.09£0.11£0.11£0.31£0.57

100V£0.07£0.06£0.06£0.08£0.08

450V

£0.15£0.18£0.30£0.48

ELECTROLYTIC AXIAL CAPACITORS

uF

0 47102.247102247100220470100022004700

16V 25V

£0.10£0.10£0.13£0.21£0.33£0.52£0.90

£0.09£0.12£0.09£0.11£0.13£0.18£0.24£0.40£0.64

63V

£0.10£0.10£0.10£0.12£0.13£0.16£0.21£0.42£0.69£1.05

100V

£0.15£0.10£0.10£0.10£0.12£0.17£0.20

450V

£0.19£0.22£0.34£0.48£1.06£1.33£2.46

SOLDERING IRONSAntex Soldering ironsM 12 WattC 15WaiiG 18WattCS 17WattXS 25WattST4 STAND35Watt Gas IronDesolder PumpAntistatic Pump22SWG 0 5Kg Solder18SWG 0 5Kg Solder1mrn 3 yds SolderDesolder Braid

£7.75£7.78£7.96£7.88£7.96£2.85£11.58£3.00E4.30£7.40£6.60£0.62£0.87

Rp CONNECTORSBNC Solder Plug 5008NC Solder Plug 75RBNC Crimp Plug 50R8NC Crimp Plug 7515BNC Solder SktBNC Chassis SktPL259 5 2mmPL259 11 mmRND UHF socketSQR UHF socketF Plug RG58F Plug RG6N Plug RG8N Socket RG8BNC Crimp Pliers

£0.93£0.96£0.68£0.68£1.08£0.80£0.68£0.62£0.68£0.45£0.30£0.27£1.60£1.40

£15.50

PCB EQUIPMENTUV EXPOSURE UNITPLASTIC DEVELOPING TRAYPHOTO RESIST AEROSOL SPRAY (100m1)FERRIC CHLORIDE CRYSTALS (0.5Kg)TIN PLATING POWDER (90g)ETCH RESIST PENPCB POLISHING BLOCK

STRIPBOARD 0 1 PITCH64rnor x 25mm £0.2764rnm a 95rnm £0.9064mm x 431 mm £3.2295mm x 127mm £1.5095mn, x 95mm95mn, x 431mrn £4.80100mrn x 160mm £1.60119mrn x 454rnm £6.20

PHOTO RESIST BOARD(0. Fibre)

CO.£1.£2.£2.

£67.38£1.35£390£2.45

£10.80£0.72£1.84

BREADBOARD81mm x 60mrn £3.06175mm x 42rnm £3.74175mm x 67mm £5.56203mm x 75mm includesmounting plate & posts £7.36

COPPER BOARD (G. Fibre)100rorn x 160mm £0.90110mm x 220mm £1.24

PHOTO RESIST BOARD(Paper)

86 £0.6762 £1.2409 £1.5841 8 rx10 £4.63

CAPACITORSCeramic Mini Disc 100 & 63V

1 OpE to 100nF1 pF 1nF £0.06 1n2i2n7 £0.073n3 -4n7 0.1210n & 12n E0.07

Polystyrene 160V 5% 47pF to 10nF47p -2n2 £0.09 2n7-100 £0.12

D CONNECTORSPlug Socket

9 Pin £0.29 £0.3015 Pin £0.39 £0.3915 Pin H.D. £0.81 £0.9023 Pin £0.40 £0.4925 Pin £0.48 £0.50

9 Way plastic cover £0.3015 Way plastic cover £0.3323 Way plastic cover £0.3625 Way plastic cover £0.36

BRIDGERECTIFIERS

W005 1 5A 50VW02 1 5A 200VBR32 3A 2008BR62 6A 200V1004 10A 4008

£0.19£0.20£0.36£0.64£1.39

SWITCHES3amp 250v 6 4rran ip mountingSPST ToggleSPOT ToggleSPOT CO TogDPDT ToggleDPDT CO ToggleD PDT CO Toggle(biased) £1.20D PDT CO Toggle(biased 1 way) £1.20OPDT mini slide £0.15Rotary Waler 1P -12W. 2P 6W3P -4W, 4P -3WKey Switch SPSTPush to makePush to breakLatching Push SqrPCB Tact 6 x 6narn

£0.58£0.60£0.64£0.68£0.76

£0.78£2.70£0.25£0.28£0.63£0.25

RESISTORS0 25W 5% CF E12 Series £0.6011000 5W 5% CF E12 Series £0.95/1000 25W 1% MF E24 Series £1.72/100POTS Log or Lin 4709 IMO 25ner dia 0.25in

shaft £0.42PRESETS Enclosed Horz

or Vert 1008 1 MO 0.15W £0.15PRESETS Skeleton Hone

or Vert 100R IMO 0 1W £0.11PLEASE STATE VALUE REQUIRED *

COMPUTER ACCESSORIES

Parallel Printer Lead 2mRS232 Lead (all pins) Male MaleRS232 Lead (all pins) Female MaleCentronics 36 Way Lead Male MaleGender Changers9 Way D Mini Female to Female9 Way D Mini Male to Male25 Way D Mini Female to Female25 Way D Mini Male to Male9 Way D Female to Female9 Way D Male to Male25 Way D Female to Female25 Way D Male to MaleAdaptors2 Was Maie to 25 Way Comae9Wav E.ernale i3 25Was Mare25 Way Male to 9 Way Female25 Way D Male to 36 Way Centronic25 Way Null Modem Female Female25 Way Null Modem Male to Female25 Way Null Modem Male to MaleRS232 Surge Protector Male FemaleRS232 Jumper Box Male to FemaleRS232 Tester (7 LEDs) Male FemaleData Switch BoxesSerial Switch box 2 Way A/BSerial Switch box 3 Way A/B/CSerial Switch box 4 Way A/13/C/DSerial Switch box Cross overParallel box 2 Way A/BParallel box 3 Way AiEliC.Parallel box 4 Way A'8IC/0Parallel box Cross over

£3.75£3.80£4.78

£1 .81f1.98£2.23E2.23E2.33£2.33£2.71£2.71

c 2 .7 1

E2 71

£2.33£3.56£3.02£3.02£302E6.12£3.02£6.59

£9.20£13.16£15.15E19.69£11.84£17.11£18.43£20.42

DIODESZener Diodes 287 33V13ZY88400Mw8Z)035 1.3W1540011 N40021540031540041540051540061 N40071 N54001554011 N54021 554041 554061 N54071 N54081 N9141N916154148BY1330A470A90059105202BA157BA158851591541490A200

£0.08£0.14£0.06£0.07£0.07£0.07£0.07£0.08£0.08£0.09£0.09£0.09£0.11£0.11£0.14£0.15£0.06£0.06£0.05£0.13£0.28£0.07£0.10£0.27£0.10£0.10£0.10£0.06£0.10

ORDERING INFORMATIONAll prices exclude VAT.

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CALL IN - OPEN: MON-FRI 8.30-5.00 SAT 10.00-5.00


26

PIC PROGRAMMERThe latest buzz in Programmable Logic Land is `PIC', a RISC -based microcontroller manufactured by Microchip TechnologyInc. Read all about it in this article! A programmer is describedwhich enables a large number of PIC16Cx and PIC17Cx devicesto be loaded with your own application programs. And there ismore good news: software development for PIC controllers willbe the subject of a short course to be featured in this magazinein the near future.

Design by M. Rose

THE sheer market force and impactof microcontroller families such as

the MCS-51 and 68xx, manufacturedby semiconductor 'giants' like Intel andMotorola, would make you almost for-get that there exist competing compa-nies in this field. One of thesecompanies is Microchip Technology inthe USA., who produce a remarkablefamily of microcontrollers designatedwith the type prefix 'PIC'.

PIC processors were developed foruse in widely different surroundingsand conditions. In the office environ-ment, for instance, you may find themlurking in photocopying machines,typewriters and barcode scanners.Computer peripheral manufacturersuse PICs in printers, scanners anddisk drives. In the telecomms sector,PICs are found in a wide range ofequipment, including fax machinesand cellular telephones. The automo-tive industry, too, employs PICs in fuel

injection systems, police radar detec-tors and anti -block brake systems.

One of the intentions of this articleis to make the advanced hobbyists andsmall-scale programmer familiar withPIC devices, and what better way to dothis than to describe a compact and in-expensive programmer? Once you havebuilt the programmer and completedthe course on PIC software develop-ment, you are ready to use these inter-esting devices in a vast range ofprocessor -controlled applications.

The programmerThe programmer circuit is designedsuch that it can be used for a largenumber of PIC devices. The hardwareremains limited to an absolute mini-mum thanks to the use of ... a PIC mi-crocontroller! The programmer iscapable of burning the following de-vices: PIC16C54, PIC16C55,

MAIN SPECIFICATIONS

28 -pin processors: PIC16C52; -55; -56;-57; -71; -84

40 -pin processors: PIC17C42Processor: EPROM or OTP

versionPrograms: Code memory and

configuration wordIC sockets: ZIF type (28 -pin

and 40 -pin)Software: On -board in

Support:RAM memory:Communication:

PIC17C42via MS-DOS PC32KBytevia RS232 interface

PIC 16C56, PIC 16C57, PIC 16C71,PIC16C84 and PIC17C42. These ICsare connected to the programmer viatwo zero -insertion force (ZIF) sockets.The PIC17C42 is fitted into a 40 -wayZIF socket, while the other PICs fit intoa 28 -way ZIF socket. If you do not en-visage ever programming either aPIC16C or a PIC17C device, the rele-vant ZIF socket may be omitted with-out problems.

The programmer is controlled bysoftware that runs on an MSDOS PC,in conjunction with the pre-pro-grammed PIC17C42 in the program-mer circuit itself. The latter PIC takescare of the communication with thePC, and generates the supply and pro-gramming voltages for the PIC to beprogrammed. The direct voltages usedin the programmer circuit are 'tailored'with the aid of the PWM (pulse -widthmodulation) outputs of the PIC17C42.This obviates the need of a host of di-rect voltage sources usually found inprogrammers.

The hardwareThe circuit diagram of the PIC pro-grammer is given in Fig. 1. First, let usdiscuss the digital section of the cir-cuit. The two ZIF sockets that receivethe PIC devices to be programmed aremarked U11 and U12. The operation ofthe circuit is not so easy to explain inone go because the PIC devices thatcan be programmed have slightly dif-ferent programming sequences. Thesesequences will, therefore, be describedseparately for each processor.

PIC17C42The PIC17C42 has an internal ROM


PIC PROGRAMMER

X1

0.2

C7

10, 16V

5V

O 116 e U14

-8- R2114 R2OUT

L MUT T2IN10

4 T1OUT T1 IN "R1IN R1OUT

12

C2. 4

MAX232

0.2

0-8--

10 161/

C11

0,16V

5V

26

25

2

10

21,

23

11

12

13

10

15

16

17

18

PAO/INT

PA1/RT

PA2

PA3

PCO/ADO

PC1/A D1

PC2/AD2

PC3/.4133

PC4/AD4

PC5/A135

PC6/AD6

PC7/AD7

POO/AD8

PD1/0.09PBOHCAP1

PB1/CAP2 PIC PD2JAD10

17C42 P03/A011PB2/PWM1 PO4/A012

PB3/PWM2 PD5/AD13

PB4/TCLK12P06/A014

P95/TCLK3PD)/4015

PB6

PB7

OSC1

2 ADO

3 ADO

4 A135

ADO

6 ADS

AD2

AD

ADO

5

4

REO/ALE

R E1 /OE

PE2/111

MCLRNPP

TEST

/02g

38

37

6

4

29

28

9 120

U9

10i ff

CTR12

>0

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T=0

0 --7-

2

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5

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2

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V

1N4148 IC3

10:16V

U1b

R4

P-L10k9

10k

RI

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U1a

2

U4

ADO 2D > 7

19 AO

AD1 3 18

6

2 4 17 A2

ADO 6 15 A4

A135 4 A5

AD6 8 13 A6

AD] 9 12 Al

Al 5V

EN

AEW

A03 5

\AL21\407 9

U274HC573

10 r> V

U7a

EN

74HC573

ADW

\ A33

D

A3 28

AO

AA

A2A2

3

A4AO

\ A5 5

\ A6 4

A4 25

/.\18 A9 A10 21

16 411^ 612 2

15 Al2/111.314 613/13 414

12

0, 19 ADO

18 AD1

6 403U6a

15 ADO A10 2

10 AD5 &

12 AD)

A9

A10

A11

Al2

413

A10

U3

RAM32K

DO

O 1

02

D3

D4

D5

O 6

07

R/W

CE y OE

20 I10 22

74HC573

U6c

5

6 2L13

812

914

1015

1

749C4040

U7c

OU7d

U7e

Ulf

111 = 74HCT32

U6 = 74HC08U7 = 74HC04U10 = 74HCT4066U13 = LM324

U7b

41 &

9

3

U6b

U d

11 600

12 AD1

13 AD2

15 A03

16 AD4

1] AD5

18 ADfi

19 A07/

9 10 13 12

fi

5

5V

U6d

P M

12

ADO

J ADI

/A02/

A134

/A05/ADO

/AD)

0901

28- OSC2

6PAO

PA1

PA2

PA3

0PBO

PB1

PB2

PB314

U11

ZIF28

MCLR

RTCC

PC7

PC6

PC5

PCO

PC3

PC2

PC1

PCO

PB7

PB6

P55

U10a28

2 AD3

2

25

2423

22

2

zo

19

18

7

6

15

RIO

C5

U10b

5

U10c 0--81 19

10

fi

U10d

2

1

PCO/ADO

PC1 /AD1 U12PC2/A132

PAO/INTPC3/A03

PA1 /R7PCOIA04

7 PC5/A05 PA2

PC6/ADS PA3

PC7/AD7RA4/RX/137

40- PDO/A138 PA5MUCK

39- PD1/AD9

38-PI30//CAP1

1.132/40I 0

37 P'33"'" ZIF403 P134/41312 PB2/PWMI35

P05/4013 PE3/PWA12

34- P136/8814

33-PM/70_102

P137/A1315PB5/TCLIO

30REO/ALE

29 PB6REVITE

23BP

PE2NTR

32MCLRNPP

27- TESTOSC1 /CLIMT a.

26

25

24

23

22

21

9 20 110

11 ADO/12 A131/

13 AD2 /10 AD3/

15 A04/16 AD5/

17 A06/8 AD]/

C6

220nR/4 R15

PWM220

C8

R12

R13

499

00n

R11

U 3d12

220n

113

220nR2

EMI EMIC14

R18

9

100n

R16

Al'

9

U13c10

220n

VDD

VPR

X2

5V

OU15

7805

j? 14 .120;123 20

UB

Tel Ton? T.17

V

0C10

00n

900048 - 11

2

Fig. 1. Circuit diagram of the PIC programmer. The circuit is a 'hybrid', i.e., a combination of digital and analogue electronics.


28 GENERAL INTEREST

(read-only memory) which contains aprogram that enables the processor toprogram itself. To enable the it to makeuse of this programming routine, theprocessor must be given access to asmall RAM (random access memory)area. This RAM is formed by U3, a 32-KByte static memory type 62256 or43256. Two octuple registers type74HC573 (U2 and U4) act as a latchwhich allows 16 -bit RAM address loca-tions to be stored. The signals neededto store data into the memory arefound on port connections PDO andPD1 of the PIC microcontroller, U5.During the programming operation,the control signals appear at port con-nections PC6 and PC7 of U12, the con-troller to be programmed. The controlsignals are combined logically by twoOR gates, UlA and U113, contained in a74HCT132.

A very special configuration is foundaround register U8. It may strike youas odd that this memory is nearly al-ways in high -Z mode, while its inputsand outputs are interconnected. Thisis not a mistake! While the IC is inhigh -Z mode (also called 3 -state), the`short-circuited' input and output con-nections carry the bit patterns to bestored in the RAM. The informationconveyed over the bus may also becopied into the register by controllingthe C input (pin 11). This happens withone byte only: the configuration word.As long as U8 is in high -Z mode, thecontents of the register remain `hidden'in the IC. The PIC17C42 to be pro-grammed reads the configurationstored in this register with the aid of apulse on port PC3. Only during thispulse is the register released from itshigh -Z state. Since the outputs of U5and U3 are then at high impedance, thecontents of U8 appear on the multi-plexed data/address bus during thisshort read pulse. In other words, U8acts as a one -byte wide memory with adepth of one location, and is used forintermediate storage of the processorconfiguration word.

The processor configuration word isbuilt by the software which runs on theMSDOS PC, and serves to define pro-gramming parameters including thetype of clock generator used, andwhether or not the PIC is to be pro-tected from being read out.

The programming status informa-tion may be found on pins PCO andPC1 of the PIC17C42 to be pro-grammed. These outputs are low dur-ing the programming operation. If theprogramming sequence is successfullycompleted, PCO goes high. If not, PC Igoes high.

The programming cycle is started byapplying a programming voltage (Vpp)of 12.5 V to the reset input, MCLR,while the test input is made high. This

is achieved by analogue switch Ulm)switching on the supply voltage of thePIC17C42, and closing thoc about 1µslater to put the programming voltageon the reset input of the processor.Next, the programming operation isstarted.

PIC16C55/57These processors come in 28 -pin DILenclosures, and differ only in respect ofthe size of their memory. Contrary tothe PIC17C42, the PIC16Cxx devicesdo not require an external memory forthe programming sequence - data issimply placed word -by -word into thePIC16Cxx by the controller in the pro-grammer circuit.

Since the 28 -pin socket is also usedto program 18 -pin PICs, a number ofsignals on the socket must be config-urable. The connection with U5, themain processor, is established by clos-ing Ulop. At the same time, the connec-tion with the programming voltagemust be broken. This is achieved withthe aid of switch U100.

The programming cycle is started assoon as the supply voltage and the pro-gramming voltage are applied to the

processor to be programmed. This isachieved with the aid of U101) and U 1 ocrespectively.

The programming algorithm usedenables selected bytes to be pro-grammed individually, and to be readback for verification. This allows themain microcontroller, U5, to keep trackof the complete programming sequence(which includes blank check, program-ming and verification) in a simple man-ner.

PIC16C54/56For these controllers, the signalarrangement on the ZIF socket is mod-ified. Switch UIOA is opened becausepin 9 is to be used for the programmingvoltage. As with the 16C55/57, thesupply voltage is applied to the socketvia 'Clot), while Uice connects the pro-gramming voltage. The programmingalgorithm is identical to that of the16C55/57.

PIC16C71/84These processors are programmed

using the same hardware settings asthe PIC16C54/56, but a different pro-gramming algorithm. This is fairlycomplex, but fortunately we need notbother about that because everythingis taken care of by the system softwarecontained in the PIC I7C42 (which issupplied ready -programmed throughthe Readers Services).

The analogue circuitryApart from digital circuitry, Fig. 1 alsoshows a fair amount of analogue elec-tronics. To begin with, there is a serialport based on the MAX232 single -chipRS232 interface. A big advantage of theMAX232 is its on -chip voltage con-verter which supplies the symmetricalvoltages needed to comply with re-quirements as regards voltage swingon an RS232 link. This converter al-lows the programmer's power supply tobe kept simple. Indeed, all that isneeded is a standard 7805 which caneasily supply the 50 mA or so drawn bythe programmer. A heat -sink is notneeded on the 7805.

The 7805 is powered by a mainsadaptor with an output voltage be-tween 15 V d.c. and 20 V d.c. The min-imum value is required to ensure theproper programming voltage, while themaximum value must be observed toprevent the 7805 from being destroyedby a too high input voltage. The partslist mentions a 12-V mains adaptor.Most of these adaptors supply a con-siderably higher output voltage thanthe nominal value when the load cur-rent is relatively low. Just to make sureit is suitable for the job, the adaptor'soutput voltage should be checked withthe programmer connected. If you usean adaptor with an internal regulator,be sure to set this for an output voltagebetween 15 and 20 V.

The desired programming voltage,Vprog, and the supply voltage, VDD,are regulated by the PWM1 and PWM2outputs of the P1C17C42, U5. Theseoutputs are connected to two activesecond -order low-pass filters, and op-erate at a frequency of about 64 kHz.The roll -off frequency of the filters builtfrom four opamps contained in anLM324, U13, is set at about 1 kHz. Thefiltered output voltage has a value be-tween 0 and 5 V depending on the dutyfactor of the PWM signal. Despite thesimplicity of the filter sections, the di-rect output voltages are sufficientlystable, accurate and virtually free ofripple. The filter is followed by a d.c.amplifier wired for a gain of three. Inthis way, a variable output voltage ofbetween 0 V and 15 V is obtained. Inpractice, VDD is usually between 4 Vand 6.5 V, while VPROG lies between12 V and 13.5 V. The output imped-ance of the opamps is low enough to


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Advanced Property Man gmenSeamless integration with simulation an

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Non -Linear & Linear Analogue Simulation.

Event driven Digital Simulation with

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with multiple analogue & digital sections.

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schematic.

o Multi -Layer and SMT support.

o Unlimited Design Capacity.o Full DRC and Connectivity Checking.o Advanced Multi -Strategy Autorouting.

o Output to printers, plotters, Postscript,Gerber, DXF and DTP bitmaps.

C Gerber View and Import capability.

apcenLien Write, phone or fax for your free demodisk, or ask about our full evaluation kit.Tel: 0274 542868. Fax: 0274 481078.Electron i C S 14 Marriner's Drive, Bradford BD9 4JT.

Proteus software is for PC 386 compatibles and runs under MS-DOS. Prices start from £475 ex VAT; full system costs £1495.Call for information about our budget, educational & Windows products. All manufacturers' trademarks acknowledged.


30 GENERAL INTEREST

PIC PROCESSORS - PORTRAIT OF A FAMILY

Below is a short discussion ofthe block diagram of thegeneric PIC16C5x processor.For full data on all devices inthe PIC family, consult theMicrochip Technology data -books.

PIC16C5xThe PIC16C5x from MicrochipTechnology Inc. is a family oflow-cost, 8 -bit wide, fully staticCMOS microcontrollers withon -chip EPROM. The core ofthe processor has a RISC struc-ture, and has an instruction setof 33 instructions. A feature ofthe RISC structure is that theCPU is capable of executingone instruction per machinecycle, except the jump instruc-tions, which take two machinecycles.The 12 -bit wide instructionshave a very compact structure.Consequently, machine codegenerated for the PIC16C5x isclaimed to be twice as compactas for other, comparable, 8 -bitprocessors. Furthermore, PICprocessors contain circuitry toreduce power drain and exter-nal component count of a com-plete system.The internal power -on resetcircuit and start-up timer en-sure that the processor is prop-erly initialized after the powersupply is switched on. Theusual hardware for this pur-pose may, therefore, be omit-ted.A choice of four oscillatortypes is available, including alow -energy oscillator based ona crystal or a ceramic res-onator, and an inexpensive RCoscillator. The EPROM versionsof the PIC16C5x (indicated bythe suffix JW) allow the user toselect the oscillator type duringthe programming of the con-figuration word. By contrast,the oscillator type selection isfixed by the manufacturer forOTP (one-time programmable)versions of the processor. Theletters after the type numberindicate which oscillators maybe used with the processor.Extensions XT and HS indicatea crystal or a ceramic res-onator; LP indicates a low -power oscillator; and RC

EPROM512 X 12 TO2048 X 12

2

INSTRUCTIONREGISTER

2

INSTRUCTIONDECODER

4111

1I PC

(*)

44.4

I DIRECT ADDRESS

STACK

STACK 2

DT TIMEOUT

RTCC coNFIGPIN

ORATION EPROM

DISABLE

WA rcHDOG

WDT/RTCCPRESCALER

DIRECT RAMADDRESS

OSCI OSC2 MCLR

OSCSELECT

'CODE 2

PROTECT'

CLKOUT

T5OPTION PEG. "OPTION"

1. FROM W

STATUS (131

1

Awe; w ALA

FROM W

RTCC (II)

flDATA BUS

FSR (IA)

OSCILLATORTIMING 8CONTROL

"SLEEP"

GENERALPURPOSEREGISTER

FILE

18

FROM W

TRISA IS

/4RAO-RAT

MIME

ABC -ART

940048 -12

FROM W

TRISC I 17

/aRCO RC]

(PIC I8C55,C57ONLY)

/8

indicates a simple RC oscilla-tor. The fourth oscillator optionis the use of an already avail-able clock signal, which maybe used on all processors.

General specificationsClock frequency: d.c. - 20 MHzInstruction time: infinite to

200 nsInstruction width: 12 bitBus width: 8 bitEPROM memory: 512 - 2K x 12Registers: 25 - 72 x 8 (SRAM)Spec. func. registers: 7

Hardware stack: 2 levelsAddressing: direct, indirect

and relative

I/O functionsI/O lines: 10 - 20RTC/counter: 8 bit with

8 -bit prescalerWatchdog timer internal, with

RC oscillatorProtection: EPROM, via fuseEnergy reduction: via sleep

mode

PIC16C71This PIC processor is an up-graded derivative of thePIC16C5x. It features, amongothers, an integrated A -D con-verter. The processor handles14 -bit wide instructions, whichare executed in one machine

Type

PIC16C54

EPROM RAM I/O pins

512x12 32x8 13 18PIC16C55 512x12 32x8 21 28PIC16C56 1Kx12 32x8 13 18PIC16C57 2Kx12 80x8 21 28

cycle. As with the 16C5x, twocycles are needed for a jumpinstruction, The processor rec-ognizes four interrupt sources,and has an eight -level stack.The on -chip A -D converter hasfour channels, a sample -and -hold function, and a resolutionof 8 bits. The tolerance is±1 LSB, while the completeconversion time is 30

General specificationsClock frequency; d.c. - 16 MHzInstruction time: infinite to

250 nsInstruction width: 14 bitBus width: 8 bitEPROM memory: 1K x 14Registers: 36 x 8 (SRAM)Spec. func. registers 15Hardware stack: 8 levelsAddressing: direct, indirect

and relative

I/O functionsI/O lines:RTC/counter:

138 bit with

8 -bit prescalerWatchdog timer. internal, with

RC oscillatorA -D converter:8 channels, 8 -bitProtection: EPROM, via fuseEnergy reduction via sleep

mode

PIC16C84The PIC16C84 is also a staticcontroller, only this type has anEEPROM program memory of1Kx14 and an EEPROM datamemory of 64 bytes Further-more, the maximum clock fre-quency is lower than that ofother PIC processors In prac-

tice, a maximum of about10 MHz is achieved, which re-sults in a minimum machinecycle length of 400 ns.

Instruction width:Bus width:EPROM memory:Registers: 36 x 8 (SRAM)Spec. func. registers: 15Hardware stack: 8 levelsAddressing: direct, indirect

and relative

General specificationsClock frequency: d.c. - 10 MHzInstruction time infinite to

400 ns14 bit8 bit

1K x 14

I/O functionsI/O lines: 10 - 20RTC/counter: 8 bit with

8 -bit prescalerWatchdog timer. internal, with

RC oscillatorProtection: EPROM, via fuseEnergy reduction: via sleep

mode

PIC17C42The 17C42 is largely similar tothe other processors in thefamily. However, it has nofewer than 55 instructions,each of which is executed inone machine cycle. At a clockfrequency of 16 MHz, a ma-chine cycle lasts 250 ns. All op -codes are 16 -bit wide, so thatinstructions can be packed in asingle 'word'. This processor iscapable of addressing a pro-gram memory of up to 64 K x16. The internal program mem-ory has a size of 2K x 16

General specificationsClock frequency: d.c. - 16 MHzInstruction time infinite to

250 nsInstruction width: 16 bitBus width: 8 bitEPROM memory. 2K x 16Registers. 232 x 8Spec. func. registers: 48Hardware stack: 16 x 16Pins: 40

I/O functionsI/O lines:Interrupts:16 -bit counters/timers.16 -bit capture registers10 -bit PWM outputs:Serial portsRTC/counter:

max 3311

3221

8 bit with8 -bit prescaler

Watchdog timer: internal, withRC oscillator

Protection EPROM, via fuseEnergy reduction: via sleep

mode


PIC PROGRAMMER

T

IM

L

X1

X2

C16

C17

C18

0000U14

U3

R18to

R210R20R19

uOR22R17

U4

U2

U8

U13

CM

c2, I

O

I el I

R 2R 5R4R 3R 6R11

\I

Pi

.LI

\II

CoUCO

U5

A

ti

U10

R113

R1

R3

C5

U 1 1

7R6 84

8 R2R9

U12

rM111 A ki47:: / -, 0--. WI 4111L. \ , )II- - - / v `-. e . ..,,,,,,--,,. ._,---,_....1/4._., __; imr A 4( NO. /-. - .0- VO.limm 0)11,

fk-0- \ fr iir-V- \' . \ 71 Thlk1 SmS . flibfl I ..L -411 /

. -'- \L=. ' ' ./.__,._ \' - . . '` --' ' - /-.0-0 - \ N OL s /-40 \ ' ._ . - \ , /

.___. \_.,. __.-,.,.,.... , , .,.._, ..__. -e--\ y V V 4 \ V 11.--/./ OM=.M. 14., L_ .. \ ). t .0 I fL lOill).,11 ale0--- N .__. \ - - -0 , ems sk ik ,- ,__, \ --(/ .._ / ---

\ -\ \ ,, if .--41,//- \- .Lits47ti . It.. est, .,...p 0i, .- l\----._, r

j r-j li---- 0,1.1-1 11 ITITh' .l .amme/ "- ! lir-.0- r/r-

amome L., I... -\ - --- th) O .1

`` - ar---la \ a

7

Fig. 2. Track layouts (direct reading) and component mounting plan of the printed circuit board designed for the PIC programmer (PCB available ready-made).


GENERAL INTEREST

Resistors:R1-R4;R6-R10 = 1041R5=270i2R11;R12;R17;R18= 1MS2R13-R16;R19-R22 = 499kO 1%

Capacitors:C1;C2 = 22pFC3;C7;C10;C11;C12 = 101.1F 16V (radial,pitch 2.5mm)C5 = 22nFC6;C9;C13;C15 = 220nEC8;C14;C17-C23 = 100nFC16 = 100gF 25V (radial)

Semiconductors:D1 = 1N4148D2 = 1N4007U1 = 74HCT32U2;U4;U8 = 74HC573U3 = 62256 or 43256U5 = PIC17C42 (order code 7161)U6 = 74HC08U7 = 74HC04U9 = 74HC4040U10 = 74HCT4066U13 = LM324NU14 = MAX232U15 = 7805

Miscellaneous:Q1 = 16MHz crystal.X1 = 9 -way sub -D socket, angled pins,

PCB mount.Ull = ZIF28 socket for wide and nar-

row ICs (e.g., ARIES, RS no.403825).

U12 = ZIF40 socket (e.g., ARIES, RS no.403831)

Printed circuit board and softwarepackage, order code 940048 (see page70).The project software (diskette andPIC17C42) is also available separatelyas order code 7161 (see page 70).

enable direct connection to the ICs tobe programmed. The variable supplyvoltage is furnished by opamps U13aand U13,1, and the variable program-ming voltage, by U13b and U13,. Notethat the LM324 is supplied direct bythe adaptor's output voltage.

ConstructionThe PIC programmer is simple to buildon the double -sided, through -plated,printed circuit board of which the art-work is shown in Fig. 2. This board isbest ordered ready-made through ourReaders Services, and comes togetherwith the PIC programmer's softwarepackage (MSDOS program diskette andPIC17C42). Solder carefully, and usesolder tin sparingly. This prevents

Fig. 3. Fully loaded printed circuit board before mounting in DB3 case.

short-circuits which can take hours topinpoint and correct. The parts list andthe component overlay on the PCBshould enable you to populate the pro-grammer board without problems.First, fit the passive components, tak-ing good care to observe the polarity ofthe electrolytic capacitors. Have a goodthink about the ZIF sockets before youmount them. The idea is to make themprotrude from the front panel of theplastic case. This is easily achieved byinserting the ZIF sockets into a stack ofnormal IC sockets. Alternatively, usewire -wrap sockets to enable the heightof the ZIF sockets above the board tobe trimmed accurately. The PCB is de-signed to fit into a type DB3 plastic en-closure from LTP. The advantage ofthis enclosure is that the PCB can besecured with the aid of two strips,which go round the problem of the ab-sence of screw holes in the board.

The PIC 17C42 (U5) is preferably fit-ted into an IC socket, so as to enable itto be replaced easily with an updatedversion. All other ICs may be soldereddirectly on to the PCB, although theuse of IC sockets is recommended ifyou want to reduce fault-finding time.

Once all components are accommo-dated on to the board, the programmermay be connected to the PC's serialport. To keep this link as simple aspossible, all necessary handshakinglines have been interconnected. Thelink is established by a 9 -to -9 pin ex-tension cable without crossed wires. Ifyour PC has a 25 -way serial port con-nector, use a 25 -to -9 pin adaptor assupplied with many mouse packages.

Control softwareThe control software for the PIC pro-grammer consists of two parts: (1) anMSDOS diskette containing the pro-gram to be run on a PC and (2) a ready -

programmed PIC17C42 which containsthe program running on the program-mer board. The software on the PCdoes all the communication with theprogrammer, and starts the necessaryroutines. Since the programmer boardis also 'intelligent', the amount of traf-fic on the serial link is reduced to aminimum.

After starting the program PIC.EXEon the PC, you are first prompted toenter the PIC type to be programmed.Obviously, only types supported by theprogrammer can be selected. After thetype selection, the program first dis-plays the type of processor, the mini-mal and maximum supply voltage, theprogramming voltage, and the name ofthe file to be burned into the device.Also shown are the options containedin the configuration word. These op-tions differ, depending on the PIC typeselected. Finally, COM1: or COM2:allow you to select between these serialports on your PC.

The file to be programmed into thePIC must already be present on thediskette or hard disk - it can not begenerated by PIC.EXE. The file formatand available instructions will be dis-cussed in the 'PIC ProgrammingCourse' to be featured in future issuesof this magazine. First, read the fileusing the 'File' menu option, and thenprogram it by selecting the option'Prog'. The configuration is burned intothe processor by selecting the menuoption 'Fuse'. Mind you, the oscillatortype selection is fixed by the manufac-turer, since it is hardware dependent.The 'Blank' option allows you to checkwhether the PIC to be programmed isempty. The function of 'Quit' is obvi-ous. An overview of available com-mands may be called up by typing '?'.



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t=-

34

FIGURING IT OUTPART 14 VARYING INPUTS

By Owen Bishop

This series is intended to help you with the quantitative aspects of electronic design:predicting currents, voltage, waveforms, and other aspects of the behaviour of circuits.

Our aim is to provide more than just a collection of rule -of -thumb formulas.We will explain the underlying electronic theory and, whenever

appropriate, render some insights into the mathematics involved.

We continue the exploration ofcircuit modelling by extendingit to deal with applied voltagesor currents that vary in time.To model a circuit with both ca-pacitive and inductive elements,we need a second -order differ-ential equation. In Part 13 weshowed that, if the elements arein series (Fig. 118) and the ap-

930010-XIV-118

Fig. 118

plied voltage is constant, theequation has the form:

dt L±_R

dti =0 [Eq. 94]

LC

But the right-hand side of theequation is zero only when wehave made the simplifying as-sumption that the applied volt-age is constant. This is an as-sumption that seldom can bemade. More often, the voltage, u,varies in a regular manner . Forexample, it may ramp up or downat a fixed rate, it may vary si-nusoidally, or it may increaseor decrease exponentially. Weneed to be able to solve equationsof the form

d2i R di 1 . 1 du±_._+_ i =_._dt2 L dt LC L dt

[Eq. 109]in which u is a function oftime.Part 13 shows how this equa-tion is obtained. The form of the

equation for a parallel LCR cir-cuit is similar (see Eq. 108 inPart 13). Remember that, al-though we are analysing only thesimplest of series and parallelcircuits, more complicated cir-cuits can often be reduced tothese cimple circuits by using thetechniques of network reduc-tion that we have discussed onseveral occasions in previousmonths.

Particular integralSolving equations with the formof Eq. 109 is done in two stages.First we solve the equation as ifthe right-hand side equals zero.The method for doing this, basedon the auxiliary equation, wasdescribed in Part 13. The resultobtained is known as the com-plementary function (CF). Atthis stage we can say that:

complemetary function = 0.

Next, we need to find somethingelse to include in the left-handside of the equation, so that theright-hand side equals (1/L)du/dt.This 'something' is known as theparticular integral (PI):

CF + PI = (1/L)du/dt.

An example shows how to findthe particular integral. Supposethat in Fig. 118: R = 500 Q,C = 200µF and L = 100 mH. Letu be a voltage that ramps up ata rate of 20t2. From these par-ameters, R I L = 5000; 1/LC= 50 000; (1/L)du / dt = 400 t. Themodelling equation is:

2 d

dt +5000 -d+ 50 000 i = 400 tdt dt

[Eq. 110]To find the CF, put the right-hand side of Eq. 110 equal to

zero:2 d

dt

di--7+ 5000

dt-+50 000i =0

[Eq. 111]The auxiliary equation ofEq. 111is

m2 + 5000m + 50 000 = 0.

Solving this by using the quadraticformula (Part 13), we find thatit has real roots: m1 = -10.02and m2 = -4990.

The CF is:

i = Ae-10.02t Be -4990t

where A and B are arbitrary con-stants which can be determinedif we are told two boundary con-ditions.

To find the particular integral,we assume that the right-handside of the solution has theform:

i=Ct+D

where C and D are constants. Ifthis is so, then:

di/dt = Cand

d2i/dt2 =0.

Substituting these values inEq. 110:

0+5000C +50 000(Ct+D)

= 400 t

55 000 Ct +50 000D = 400t

[Eq. 112]We solve this equation by look-ing at the coefficients of the pow-ers of t. The highest power of tis tl. On the left, its coefficientis 55 000C; on the right, its co-efficient is 400. For Eq. 112 tobe satisfied by all possible valuesof t, these coefficients must be

equal:

55 000C = 400C = 400/55 000

= 7.27 x 10-3.

The coefficient of t0 is D on theleft. There is no term in t0 onthe right, so the coefficient iszero:

D = 0.

The PI is:

i = t(7.27x10-3).

The complete general solutionis:

Ae-10. 02 t +Be -4990 t

+t(7.27x10-3)

[Eq. 113]The first two terms in this gen-eral solution are like those ob-tained in Part 13 for a constantapplied voltage. Now we have anadditional term to allow for thefact that the voltage is ramp-ing.

In this example we assumedthat the right-hand side of theequation has the form Ci + D.This was based on the fact thaton the right-hand side of Eq. 109the highest power of t is t1. If tis of higher power or there are

Form of AssumedRH side function

k Ckt Ct+Dkt2 Ct2+D+E

k sin t Ccost+Dsintk cos t

ekt Cekt

Box 1. Functions for particularintegrals (k is a constant).


FIGURING IT OUT - PART 14

other functions of t, different as-sumptions are made. Box 1 listsforms suitable for other cases.

We can now proceed, as usual,to find a particular solution (notto be confused with the particu-lar integral). This is the solu-tion obtained when two borderconditions are satisfied. Let usassume that, when t = 0, i = 0.Also, when t = 0.01, i = 1 mA.Substituting the conditions fort = 0 in Eq. 113:

0 = A + B

B = -A.

The equation becomes:

Ae-- 10 02 t Ae-4990t

+t(7. 27x 10 -3)A(e-1o.o2t -4990t

+t(7.27x 10 )

[Eq. 1141Substituting in Eq. 114 the valueswhen t = 0.01:

0.001 = A(e-0 1002 - e-49.9)

+7.27x10-5= 0.9047A + 7.27x10-5

andA= (0.001- 7.27x10-5)/0.9047

= 0.001025.Substituting these values in

Eq. 114, we obtain the particu-lar solution:

i= 0.001025(e-10.021 -4990 t

+t(7. 27x 10 -3)

[Eq. 115]The graph of Eq. 115 for

0<t<0.01 appears as Fig. 119.It shows the rapid increase of cur-rent; this is necessary in orderto meet the condition that i =1 mAwhen t = 0.01 s. Remember thatwhen we specified that i = 0 whent = 0, this only means that i iszero at that instant. In actual-ity, it is passing through zero atthat instant to reach a relativelyhigh level soon after. Specifyingzero current at zero time does notmean that there is no charge onthe capacitor and no magneticflux in the inductor. These musthave been present as the resultof a voltage applied to the cir-cuit before t = O. This is why thecurrent increases so rapidly.However, the effects of this dieaway and the current begins todecrease. After about 10 ms, thecircuit begins to show the ef-fects of the new voltage ramp-ing up from 0 V at t = 0. The ef-fects of this are better shown onthe right of Fig. 119, which is

j kt A

f

1000

800

600

400

200

2 3 10 20 30 40 50 60

t/ms

Fig. 119

plotted on a longer time scale. Wecan see that the current increasessteadily, keeping pace with theupwardly -ramping applied volt-age.

To simulate the conditions inwhich the current begins with nocharge on the capacitor and noflux in the inductor, we makethe first border condition i = 0when t = 0 as before. The sec-ond condition is that di/dt = 0when t = 0. In words, the cur-rent is constant at zero whent = O. This makes B = -A as be-fore and we obtain Eq. 114.Differentiating Eq. 114:

di=A( -10. 02e -10.021

dt

+4990 e-499°1 )+ 7.27 x 10-3

Inserting the second border con-dition:

0 = A(-10.02 + 4990) +7.27x10-3and

A = (7.27x10-3)14979.81.46x10-6.

The particular equation is:

i = (1.46x10-6)(e-10.02t_e-49901)+t(7.27x10-3).

It can be seen that, because A isso small, the final expressiondominates the equation. Currentincreases at the rate of 7.27 mAper second without the appre-

930010-XIV-119

ciable initial 'kick' of Fig. 119.

Operator DBefore we model any further cir-cuits, we will look at a techniquethat often simplifies finding thesolution of differential equations.This method is based on a dif-ferent way of symbolizing dif-ferentiation. Instead of writingdi/dt, we write Di. D is not aquantity or variable, but an op-erator, which means 'differen-tiate'. We usually refer to it asoperator D. We are using it torepresent differentiation ofi withrespect to t, but it can be usedfor any other pair of variables,for example x and y. Using thissymbol, Dx3 = 3x2. The rules ofdifferentiation apply exactly asusual.

The idea of D is extended todifferentiating a differential. Weobtain the second differential:

2 d2iD(Di)=D t =-2-dt

Similarly, we have the reverseoperation, represented by thesymbol 1/D, which means 'inte-grate':

x 4/D = x 5/5 .

Note that we do not introduce theconstant of integration when weare working with D.

Representing Eq. 109 in terms

1 F(D) eax = eax F(a)2. F(D) {e* f(x)} = elm F(D + a) f(x)3a. F(D2) sin ax = F( -a2) sin ax

3b. F(D2) cos ax = F( -a2) cos ax

Box 2. Operator D theorems.

of operator D gives:

2 1D i+-R Di+-LC i=u

[Eq. 116]Now comes the interesting pointabout D. Although we have saidit is not a variable, it can beshown that it can be manipu-lated in equations and behave asif it were a variable. For exam-ple, we can factorize the left-hand side of Eq. 116:

1(D2+1D+LC-)

i u

There is no advantage in usingoperator D with such an equa-tion, which is easy enough tosolve by the method used above.Operator D really comes into itsown when we are modelling cir-cuits in which input voltagesvary sinusoidally (or cosinus-oidally) or exponentially. For ex-ample, consider a series LCRcircuit as in Fig. 118, but withthe following values: R = 1.5 Q,C = 1 F and L = 0.5 H. The inputvoltage , u = -(cos 3t)/6, is sinu-soidal. Calculating coefficientsgives: R 1 L = 3 and 1/LC = 2.Differentiating u and dividing byL produces sin 3t. The equationmodelling this circuit is:

d2i di-rs-+ 3-+ zt = sin 3tdt` dt

[Eq. 117]When using operator D, we

first find the complementary func-tion in the usual way. The aux-iliary equation is:

m2 +3m +2 = 0.

Although we nearly always needto use the quadratic formula tosolve this equation, there arecases like this one in which it fac-torizes easily:

(m + 1)(m + 2) = 0,

so that m1 = -1 and m2 = -2.Both roots are real and so theCF is:

i = AE -1 +Be -21.

We make use of operator D forfinding the particular function.

The advantage of D is thatthere are three very helpful the-orems associated with it. Theirproofs are rather lengthy, so wedo not have space here to ex-plain them. The theorems arestated in Box 2. They look ratherobscure, but they are easy to useas will be shown by this exam-ple. First, rewrite Eq. 117 in terms


36 GENERAL INTEREST

=3D-7

of D:

D2i +3Di + 2i = sin 3t.

Factorizing:

(D2 + 3D + 2)i = sin 3t,

whence

1i=

D +3D+22-sin 3f

Notice how we move the termsin D across from one side of theequation to the other, just as ifthey were variables. Now lookat Theorem 3a in Box 2. This tellsus that, if we have a function ofD which includes D2, and this ismultiplied by sin ax (in which ais a constant), we can replaceD2 by -a2. In this example, wehave t as the variable instead ofx. The constant a is equal to 3,so we replace D2 by -32, whichis -9:

1sin 3f

-9 + 3D + 21

sin 3t

Having eliminated the D2, it re-mains for us to eliminate the D.We juggle with the fraction onthe right, multiplying top andbottom by 3D + 7:

3D+7i= sin 3t

(3D -7X3D+ 7)

= 3D+7 sin 3t9D-, -49

Once again, we have D2 in the de-nominator, so we use Theorem3a again and replace D2 with-9:

. 3D+7sin dt

-81-493f

= -(3D +7).sm.130

-(3D sin 3t+7 sin 3t)130

The term 3D sin 3t means 'threetimes the differential of sin 3t',which equals 9 cos 3t and thePI becomes:

. -(9 cos 3t+7 sin 3t)130

Thus, the general solution (CF+ PI) is:

. Ae-t +BC2t-(9cos3t+7sin30-130

[Eq. 118]Eq. 118 has two arbitrary con-stants so it can be solved, given

[mA]

100-

-100-

5V

R1

Ok

C1

2207

Fig. 120

930110-XN-1f

C2 R2

5000u

50

[V]t

-02

- 0.1

0 t

[ms]

- -0.2

L1

200mH

Fig.

two border conditions. Fig. 120shows the graph of the solution,given i = 0 and di/dt = 0 at t = 0.Note how the curve begins withzero gradient (di/dt = 0). After theinitial upsurge, the current set-tles down to a sinusoidal form,symmetrical about the x-axis, andlagging slightly behind the inputvoltage.

Exponential inputIn Fig. 121 the input to the op-erational amplifier rises expo-nentially. The opamp is a voltagefollower, so the input to the LCRcircuit follows the same curve.The switch is set to charge C1 to5 V. When t = 0, the switch isset to discharge C1. It can beshown by the methods describ-ned in Part 12 that:

u = 5e -0.4545t.

The coefficients for the equationmodelling the LCR circuit are

930010-XIV-121

121

R /L = 250 and 1/LC =1000. Theequation is:

2i idi+ 250 --+ 1000 io dt

= -11.3625 a-0.4545 t

[Eq. 119]The auxiliary equation is:

m2 + 250m + 1000 = 0

and its roots are m1 = -4 andm2 = 246 (approximately). TheCF is:

Ae-4t Be -246t.

As before, we use D to find thePI. Writing Eq. 119 in terms ofD:

(D2 + 250D + 1000)i= -11.3625e-04545t

. _11.3625e -0.4545tt =

D- +250D + 1000

Theorem 1 is the appropriatechoice since the right-hand sideof Eq. 119 is simply an expo-nential term involving t only inthe index of e. To apply the the-orem, we have only to write theexponential term as it stands,but to replace D by a. This makesthe calculation easier than theprevious example. In this ex-ample, a = -0.4545, so we find:

-11. 3625-a 4545ti -

-O. 45452 + 250 x-0.4545 +1000

= -0.0128 e4'4545 t

This is the PI. Adding this tothe CF, we obtain the completesolution:

i= Ae-4t÷Be-246t

+( -0. 0128 e -414545t

Given two border conditions, wecan find A and B in the usual wayand so obtain the particular so-lution.

This month, we have mod-elled only series LCR circuits,but parallel circuits can be mod-elled in a very similar way andsolved using operator D.

[To be continued]

Test yourself1. Given the complete solution

of Eq. 118 and the border con-ditions that i = 0 and di/dt= 0 when t = 0, find the par-ticular solution.

2. Given the complete solutionof Eq. 119 and the border con-ditions that i = 0 when t = 0,and i =10 mA when t =100 ms,find the particular solutionand calculate i when t = 250 ms.

3. Given a circuit as in Fig. 118,with R = 100 fl, C = 2000 µF,L = 10 mH, and u = 0.08e0.5t,write the modelling equationand the general solution. Giventhat when t = 0, i = 0 mA anddi/dt = 4 A s-1, find the par-ticular solution. Calculate thecurrent when t = 100 ms.

Answers toTest yourself (Part 13)1. i = -0.01e-2500t cos 9354t

- 0.03457e -2500t sin 9354t.Underdamped. At 0.0008 s,i = -4.85 mA.

2. i =1.0097e -9.11 -0.9097e -9990.9t.After 0.5 ms the current peaksat 1 A, then falls to 0.406 Aat 100 ms. It falls to 0.01 Aafter 255 ms.



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42

DIRECT CONVERSION RECEIVERS(PART 1)

SOME NOTES ON DESIGN AND CONSTRUCTION TECHNIQUES

The direct conversion or synchrodyne receiver was invented several decades ago, butonly with the advent of modern semiconductor technology has it come into its own asa viable design alternative. Although most designs are intended for novices, and lack

certain features of high-grade superheterodyne receivers, the modern directconversion receiver (DCR) is capable of exciting performance.

Acase can be made for the assertionthat the modern DCR is capable of

performing as good as many middlegrade communications receivers.Although that assertion may seem verybold indeed, the results of my literaturesearch and experience building severaldifferent models bears it out. While noone, least of all this author, would repre-sent the DCR as capable of the best pos-sible performance, modern designs areno longer in the hobbiest curiosity cate-gory. In this two-part article you will findthe basic theory of operation, some of theappropriate circuits, and some of the ac-tual designs tried on the workbench.

Basic theory of operationThe DCR is similar to the superhetero-dyne in underlying concept: the receiverradio frequency (RF) signal is translatedin frequency by nonlinear mixing with alocal oscillator (LO) signal (`heterodyn-ing'). Figure 1 shows the basic block dia-gram for the 'front end' of both types ofreceiver. The mixer is a nonlinear ele-ment that combines the two signals, FRFand FLo. The output of the mixer con-tains a number of different frequenciesthat obey the relationship:

Fe = m FR ± n FLO [1]

Where:Fe is the output frequency;FRF is the frequency of the received radiosignal;FL, is the frequency produced by thelocal oscillator;(All frequencies in same units).m and n are integers (0; 1, 2, 3, ...).

All frequencies other than FRF and FLUare product frequencies. In general,we are only interested in the cases wherem and n are either 0 or 1, so the outputfrequency spectrum of interest is limited

By Joseph J. Carr, B.Sc., MSEE

Fig. 1. Block diagram of the heterodynefrequency conversion circuit that forms thebasis of both the superheterodyne and directconversion receivers (DCR). In the DCR, FL()

FRP

to FRF and FLo plus the product frequen-cies (Fu+FL0), and (FRF FLo). The lattertwo are called sum and difference in-termediate frequencies (IF). Otherproducts are certainly present, but forpurposes of this discussion are regardedas negligible.

In a superheterodyne radio receiver, atuned bandpass filter will select either

the sum IF or the difference IF, while re-jecting the other IF, the LO and RF sig-nals. Most of the gain (which helpsdetermine sensitivity) and the selectivityof the receiver are accomplished at the IFfrequency. In older receivers it was al-most universally true that the differenceIF frequency was selected (455 KHz and460 KHz being very common), but inmodern communications receivers eitheror both might be selected. For example, itis common to use a 9 -MHz IF amplifieron high frequency (HF) band shortwavereceivers. On bands below 9 MHz, thesum IF is selected while on bands above9 MHz the difference IF is selected. Apopular combination on amateur radioreceivers uses a 9 -MHz IF combined witha 5 to 5.5 -MHz variable frequency oscil-lator. To receive the 75/80 -meter band(3.5 to 4.0 MHz), the sum IF is used. Thesame combination of LO and IF frequen-cies will also receive the 20 -meter (14.0to 14.4 MHz) band if the difference IF(i.e., 14.0-5 = 9 MHz) is used.

In a DCR, on the other hand, only thedifference IF frequency is used (seeFig. 2). Because the DCR LO operates atthe same frequency as the RF carrier, oron a nearby frequency in the case of CW

InputSignal

Conditioning

RFAMP

RF GainControl

Mixer

LocalOscillator

Low -PassFilter

VolumeControl

940015 - I - 12

Fig. 2. Block diagram of a generic direct conversion receiver.


DIRECT CONVERSION RECEIVERS - 1 43

and SSB reception, the difference fre-quency represents the audio modulationof the radio signal. Amplitude modulated(AM) signals are accommodated by zero -beating the LO to the radio signal signalmaking Fix, = FRF(carner)' Thus, only therecovered upper and lower sidebands willpass through the system, and they are ataudio frequency.

For CW signals (morse code on -offtelegraphy), and single sideband signals,it is necessary to offset the LO frequencyslightly to recover the signal. For the CWcase one must select a comfortable tone(which is an individual preference). Inmy own case, I am most comfortableusing an 800 -Hz note when copying CW,so will offset the LO from the RF by800 Hz. For example, when copying a CWsignal at, say, 3650 KHz, the LO will betuned to either 3649.2 KHz or3650.8 KHz. In either case, the beat noteheard in the output is 800 Hz. Singlesideband (SSB) reception requires an off-set of the order of 1.8 to 2.8 KHz forproper reception.

As was true in the superheterodynereceiver, most of the gain and selectivityin the DCR is provided by the stagesafter the first mixer. While the super-heterodyne uses the IF amplifier chainfor this purpose, followed by second de-tection and audio amplification, the DCRmust use only the audio amplifier chain.Thus, it becomes necessary to providesome very high gain audio amplifiers andaudio bandpass filtering in the DCR de-sign.

One implication of DCR operation isthe lack of single signal operation. BothCW and SSB signals will appear on bothsides of the zero -beat point (F,F=FLo ex-actly). While this feature can be a prob-lem, it has at least one charmingattribute on SSB reception: the DCR willreceive LSB signals on one side of zero -beat and USB signals on the other side ofzero -beat. There have been attempts toprovide single -signal reception of SSBsignals on DCRs' by using audio andVFO phasing circuits (in the manner ofthe phasing method of SSB generation).That approach greatly increases the com-plexity of the receiver, which may makeother design approaches more reasonablethan DCRs.2

The most basic implementation of theDCR (Fig. 2) required only a mixerstage, a local oscillator and an audio am-plifier. In fact, if the mixer has a highenough output signal level, and high im-pedance earphones are used to detect theaudio, some designs can make do withoutthe audio amplifier. These are, however,a rarity and the one version that I trieddid not work very well.

In some DCR designs, there will be op-tional RF input signal conditioning con-sisting of either a low-pass filter,high-pass filter, or bandpass filter (as ap-propriate) to select the desired signal orreject undesired signals. Without some

RFTr1

LO: .7dBmRF: < .1.1dBm

Tr2

LO Input(+7dBm)

D2

Blue Pin Bead

1 3 5 70 0 0 00 0 0 0

4 6 8

Bottom View

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SRA - I - I

SBL - I

SBL - I - I

SBL - IX

Ground 2,5,6,7 2,5,6,7 2,5,6,7

LO In 8 8 8

RF In 1 1 3,4

IF Out 3,4 . 3,4 * 1

* Pins 3 4 to be connected togetherBlue bead indicates Pin 1

940015 -1-13

Fig. 3. Internal circuit of the SRA-1 and SBL-1 passive double balanced mixers. Inset showspin -outs on device package.

frequency selection at the front end, themixer is wide open with respect to fre-quency, and may be unable to preventsome unwanted signal, or spurious com-binations of signals, from entering thereceiver circuits. Some designs will in-clude more than one style of filter. Forexample, a popular combination uses asingle staged tuned resonant circuit atthe input of the mixer to select the RFsignal to be received and a high-pass fil-ter - with a cut-off frequency, Fe, of2,200 KHz - which is designed to ex-clude AM broadcast band signals. Thereason for such an arrangement is thatthe AM signal may be quite intense,being of local origin, and is therefore ca-pable of overriding the minor selectivityprovided by the tuned circuit.

The RF amplifier used in the front-end is also optional, and is used to pro-vide extra gain, and possibly someselectivity. The gain is needed to over-come losses or inherent insensitivity inthe mixer design. Not all mixers requirethe RF amplifier, so it is frequentlydeleted in published designs. In general,RF amplifiers are used only in DCRs op-erating above 14 MHz. Below 14 MHz,signals tend to be relatively strong andman-made noise tends to be muchstronger than inherent mixer noise.3

Mixer circuitsThe principal element in any direct con-version receiver (DCR) is the mixer. Themixer is a nonlinear circuit that exhibitschanges of impedance over cyclical excur-sions of the input signals. When mixinglinear, one signal will ride on the otheras an algebraic sum, but the product fre-quencies are not generated. A mixer thatproduces product frequencies can be usedeither in DCRs or superheterodyne re-ceivers. In superheterodyne receiver ter-minology it is common to call thefrequency translation mixer that pro-duces the IF a first detector, and the

mixer that recovers the audio modula-tion either a product detector or seconddetector, even though the same type ofcircuit can be used for both cases.

There are any number of mixer cir-cuits used in radio receivers, and most ofthem are candidates for use in direct con-version receivers. As you will see, how-ever, not all mixers are created equal, sosome are better suited to DCR applica-tions than others. In nearly all cases, theoutput circuit of the mixer will be a low-pass filter that passes audio frequencies,but not RF frequencies.

Two issues seem to predominatemixer selection: sensitivity and dy-namic range. The former determineshow small a signal can be detected, whilethe latter determines the ratio betweenthe minimum detectable signal and themaximum detectable signal. There aresome passive mixers that produce somuch loss, so much noise and require somuch signal strength to operate in thefirst place that they are simply not suitedto DCR design unless adequate pream-plification is provided. Such detectorscan sometimes be put to good use in su-perheterodyne receivers because they arepreceded by the gain of the front-end andthe IF amplfier chains, which can be con-siderable.

There are two issues that must be ac-counted for when selecting or buildingthe mixer element of the DCR. First,there is always the possibility of radia-tion of the local oscillator (LO) signalthrough the antenna. In order to preventthis problem, it is necessary to keep themixer unilateral, i.e. signal flowing onlyin one direction. Some mixers are inher-ently good in this respect, while othersare a bit problematical. In cases whereLO radiation might occur it is recom-mended that an RF amplifier be usedahead of the mixer, regardless ofwhether or not it is needed for purposesof improving sensitivity.

The second problem that must be rec-


44 RADIO AND TELEVISION

Fig. 4. Balanced mixer based on the CA3028A IC device.

ognized is transmission of the RF or LOsignals to the output of the mixer. Manyforms of mixer are particularly bad inthis respect, while others are consider-ably better. Theoretically any mixer canbe used for the front-end of the DCR,however, the simple halfwave rectifierdiode envelope detectors are not at allrecommended.

Perhaps the best passive form ofmixer is the double balanced mixer(DBM) of Fig. 3. This circuit provides su-perior suppression of the LO and RF sig-nals in the output, leaving only the sumand difference IF frequencies. This typeof mixer uses the same sort of diode ringcircuit as the single balanced mixer dis-cussed above, but adds a second trans-former to the circuit for the RF signal. Inthis circuit, the LO signal is driven inpush-pull across two opposite nodes ofthe diode ring, while the RF signal drivesthe alternate nodes in push-pull.

All of these diode mixers can be madewith either hot carrier diodes (preferred)or ordinary silicon small -signal orswitching diodes (those in the 1N914 and1N4148 class are suitable). In eithercase, performance is improved if thediodes are matched. While matching isbest done on an oscillographic curvetracer, silicon switching diodes can becrudely matched by comparing forward

and reverse resistance readings obtainedwith an ohmmeter. Although not an opti-mal match, the resistance matchingscheme results in superior performanceover randomly selecting the diodes.

One of the most popular forms of com-mercial DBM is the Mini -Circuits (P.O.Box 166, Brooklyn, NY, 11235, USA;phone 718-934-4500) SRA-series andSBL-series devices. The pin pattern forthe shielded case of these mixers isshown as an inset to Fig. 3, while the pinassignments are shown in the associatedtable. Note that pin 1 is indicated by ablue bead insulator around the pin, whilethe other pins will have a different color.Also, on the top of the mixer case the let-ters `MCL' appear (which is the manufac-turer's logo), and the 'M' is positioneddirectly above pin 2. These mixers areused in many published DCR designs,where they have proved an excellentchoice. They are designed for 50-Q inputand output impedances, so are relativelyeasy to match with tuned circuits and LCfilters. The RF signal must be kept at+1 dBm or below, while the LO signalmust be around +7 dBm. At an imped-ance of 50 Q, the +7-dBm signal levelrepresents about 5 mW, or 500 mV,.,,(1.4 Vpp ).

An active mixer can be built with anyof several different integrated circuits, ortheir discrete equivalents. One approachuses analog multiplier circuits, while an-other uses simple differential amplifiercircuits. The mixer of Fig. 4 is based onthe CA -3028A differential IF/RF ampli-fier IC. The differential input impedance(pins 1 to 5) is of the order of 1 kQ, whilethe differential output impedance (pins 6to 8) is 8 kQ. For an input circuit, there-fore, a transformer is needed that con-verts the antenna impedance (typically50 Q) to 1000 Q. This transformer canhave a tapped primary that matches

50 Q at the tap, while still providing tun-ing action to select input signals. Theoutput network consists of an audiotransformer with a 10-k4 primary and alower impedance secondary. The audiooutput of this circuit is quite low, despitebeing an active circuit, so it must be fol-lowed by considerable audio gain (80 to100 dB).

Considerations for goodDCR designsIt probably does not surprise many read-ers that there are some principles of gooddesign that result in superior DCR per-formance. Some of these principles werediscussed by Campbell; and others4.Even relatively simple DCR designs, in-cluding those based on the SigneticsNE602 integrated circuit double bal-anced modulator' and the popularLM386 audio amplifier, have proven tobe very sensitive and free of hum and mi-crophonics, even though that combina-tion is not without critics. Dillon'sdesign, which was tested in the laborato-ries of the American Radio Relay League(ARRL), proved remarkably free of theproblems often associated with simpleDCR designs.6

One method for terminating the mixeris to place a resistor -capacitor (RC) net-work across the IF OUT terminals of themixer and ground (see Fig. 5). The SBL-1 is designed for 50 Q input and outputimpedances, so the device is terminatedin it characteristic impedance at RF fre-quencies by the 51-Q resistor (R1).Because capacitor C1 has a value thatproduces a high reactance at audio fre-quencies (AF), and a low reactance at RF,the mixer is terminated for any residualLO and RF signal (which are absorbed byR1), but AF is transmitted to the low-pass filter.

C2 C3 36 CTCShn :10u

1 n 1

NM C9C10 T470p

MAINTUNING

Tr2270p r --

C12

365p 120p

(values for 3.5MHz band)

100nI=15

940015 - I - 16

Fig. 5. Block diagram of mixer output circuitused in direct conversion receivers. Fig. 6. Direct conversion H.F. receiver using the NE602 and LM386 integrated circuits.



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940015 I 17

Fig. 7. Direct conversion receiver based on the TDA7000 integrated circuit.

Some practical designapproachesThe NE602 type of DCR is relatively easyto build, and provides reasonable perfor-mance for little effort. The NE602 chip isrelatively easy to obtain, and for themost part is well behaved in circuits (i.e.it does what it is supposed to do). It hasabout 20 dB of conversion gain, so canhelp overcome some circuit losses, andreduces slightly the amount of gain re-quired of the audio amplifier that fol-lows. The NE602 can provide very goodsensitivity, on the order of 0.3 µV is rela-tively easy to obtain, but lacks somethingin dynamic range. Although the specifi-cations of the device allow it to acceptsignals up to -15 dBm, at least onesource recommended a maximum signallevel of -25dBm7. At higher input signallevels, the NE602 tends to fall apart.'The newer NE612 is basically the samechip, but has improved dynamic range.While I have not personally tried thenewer variety, it is reputed to be agreatly improved device compared to theNE602.

The Dillon design shown in Fig. 6uses the push-pull outputs of the NE602(i.e. both pins 4 and 5), and is superior tothe single -ended variety. According toDillon, the balanced output approach im-proves the performance, especially in re-gard to AM BCB breakthrough. Alsohelping the breakthrough problem is theuse of a 47-nF capacitor across the out-put terminals of the NE602.

Daulton takes exception to the use ofthe NE602 as the DCR front-end, andprefers instead to use the TDA7000 chip.While functionally similar to the NE602,the TDA7000 is more complex and is saidto deliver superior performance with re-spect to dynamic range and signal over-load characteristics. Figure 7 shows aDCR front-end circuit based on theTDA7000 after Daulton's design. This

circuit uses the same balanced front-endas other designs and, like the typicalNE602 design, uses the internal oscilla-tor for the variable frequency oscillator(VFO). The circuit following this front-end should be of the sort typically foundin the NE602 designs. This particularvariant uses the internal operational am-plifiers of the TDA7000 to provide activebandpass filtering.

Figure 8a shows the passive diplexerused by Campbell'. It consists of severalinductor, resistor and capacitor elementsthat form both low-pass and high-passfilter sections. The values of the induc-tors (L1, L2 and L3) are selected withtheir d.c. resistance in mind, so it is im-portant to use the originally specifiedcomponents, or their exact equivalentsin replicating the project. Campbell usedToko Type 1ORB inductors: L1 is a181LY-392J, L2 a 181LY-273J and L3 a181LY-273J.

The matched 50-52 audio preamplifieris shown in Fig. 8b, and is an improvedversion of the Lewallen circuit.According to Campbell, this circuit pro-vides about 40 dB of gain, and offers anoise figure of about 5 dB. The range ofinput signals that it will accommodateranges from about 10 nV to 10 mV, with-out undue distortion. These specifica-tions make the amplifier a good match tothe DBM. Like the Lewallen circuit, theCampbell circuit uses a grounded baseinput amplifier (T,), and an active decou-pler (T2). But Campbell also adds anemitter follower/buffer amplifier (T3).

A set of three passive audio filters,which can be switched into or out of thecircuit, is shown in Fig. 8c. These filtersare designed for termination in an im-pedance of 500 52. Three different band -passes are offered: 1 KHz, 3 KHz and4 KHz. The 4-KHz filter is a fifth orderButterworth design, while the 3-KHz fil-ter is a seventh order elliptical designafter Niewiadomskim. The 1000 Hz de -

a

from DBM RI

b

AF

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A MIK

ALL <0113TONOTYPE 101315

500

18rnH

to Audio Amplifier

940015 - I -18e

100m 100.1 100mFI

2-r I a" an940015 I ISc

Fig. 8. a) Diplexer circuit used to terminatethe mixer and filter the audio; b) audiopreamplifier for direct conversion receiver;c) audio bandpass filters with three switchselectable bandpass characteristics.

sign is scaled from the 3000 Hz design.Campbell claims that these filters of-fered a shape factor of 2.1:1, with an es-sentially flat passband "...with roundedcorners, no ripple and no ringing."

Campbell implied the use of switch-ing, as shown in Fig. 8c, but did not ac-tually show the circuitry. As shown here,the switching involves use of a pair ofganged SP3P rotary switches. In a shorttime in the future I will be working on aPIN diode switched variant for a differ-ent purpose, and see no immediate rea-son why it shouldn't work.

A complex DCR was designed byBreed, and reported in the amateur radioliterature as a direct conversion singlesideband receiver.' The single sideband(SSB) mode is properly called singlesideband suppressed carrier ampli-tude modulation, for it is a variant ofAM that reduces the RF carrier and oneof the two AM sidebands to negligiblelevels. This mode is used in HF transmis-sions because it reduces the bandwidthrequired by half, and removes the carrierthat produces heterodyne squeels on theshortwave bands.


DIRECT CONVERSION RECEIVERS - I 47

Fig. 9. Phasing -style direct conversion receiver for improved single sideband reception.

There are two methods for generatingSSB. The most common today uses a dou-ble balanced modulator to combine afixed carrier and the audio signal to pro-duce a double sideband suppressed car-rier output signal; the unneededsideband is then removed by filtering.The older and more complex variant usesa phasing method of SSB generation.Breed uses the inverse process to demod-ulate SSB signals in a clever, but com-plex, receiver design (Fig. 9). This circuitsplits the incoming RF signal into twocomponents and then feeds them both toseparate mixers. These mixers are dri-ven 90 degrees out of phase by a VFOthat produces -45° and +45° outputs.The respective outputs of the mixers areamplified and then fed to bilateral 90°audio phase shift networks where theyare recombined. The output of the phaseshift network is filtered in a low-pass fil-ter and bandpass filter, to provide the re-covered modulation.

Audio circuitsThe audio chain in the direct conversionreceiver tends to be very high gain inorder to compensate for the low outputlevels usually found on the mixer cir-cuits. The principal job of the audio am-plifier is to increase the signal level by

Fig. 10. Audio stage based on the LM386audio integrated circuit.

an amount that will create a comfortablelistening level, while also tailoring thebandpass characteristics of the overallreceiver to limit noise and other arti-facts. Although any number of discreteand integrated circuit (IC) circuits aresuitable, most designers today tend touse the IC versions. Figure 10 shows asimple LM -386 design, while the pub-lished literature shows many other de-signs as well."

The LM386 design of Fig. 10 is thesingle -ended configuration for theLM386 low -power audio stage. This ICdevice contains both preamplifiers andpower amplifiers for a nominal outputpower of 250 mW. The LM386 series ofaudio power ICs are easy to use, but be-cause of the high gain needed will oscil-late if layout is not correct, or ifgrounding is not proper. There are twobasic circuit configurations for theLM386. The differential version wasshown in Fig. 6 (Dillon's design), whileFig. 10 shows the more common single -ended design. The gain of the circuit canbe either 46 dB (x200) when capacitor C2is used, or 26 dB (x20) when C2 is deleted(leave pins 1 and 8 open -circuited).

Local oscillator circuitsThe local oscillator (LO) for a continu-ously tunable receiver of any descriptionis basically a variable frequency oscilla-tor (VFO). Although higher grade re-ceivers today typically use frequencysynthesis techniques for generating theLO signal, the standard inductor -capaci-tor (LC) controlled VFO still has appealfor less complex receivers. The VFO usedfor the LO in receivers is pretty much thesame as the VFO in transmitters, sotransmitter VFOs are frequently used.There are some cases, however, where areceiver LO has at least one specificationthat is more rigid than the transmitterequivalent: many receivers have a re-quirement for low FM phase noise. In themain, however, amateur radio applica-tions of direct conversion receivers typi-cally use the transmitter VFO for the

receiver as well.Several different VFO designs are

used for receiver LOs: Armstrong,Hartley, Colpitts/Clapp and an ampli-tude limiting design. The first three ofthese circuits are recognized according tothe nature of their respective feedbacknetworks, while the other is recognizedby the special connection of a trans-former. Note that the Colpitts and Clappare basically the same circuit, exceptthat the Colpitts uses a parallel tunedLC frequency setting network and aClapp oscillator uses a series tuned LCnetwork.

VFO circuits consist of an active ele-ment (transistor, IC, etc.) and a feedbacknetwork that must meet the Bark-hausen criteria for feedback oscilla-tors: 1) the loop gain of the circuit mustbe unity or greater, and 2) the feedbackmust be in -phase with the amplifierinput signal. In most circuits, there is180 degrees of phase inversion betweeninput and output, so the feedback net-work must provide an additional 180 de-grees at the desired frequency ofoscillation. In practical terms, for HFVFO circuits these criteria result in aneed for a gain -bandwidth product (F,) ina bipolar transistor of 250 MHz or moreand a gain (H,) greater than ten. Thehigh F, prevents unplanned phasechanges at higher frequencies within theVFO range. For field effect transistors atransconductance of 2,000 siemens ormore is usually required. In this article Ihave somewhat arbitrarily selected the

Fig. 11. Hartley VFO circuit.

)1,5 50011

C2

Fig. 12. Colpitts VFO circuit.



Fig. 13. Low -noise HF VFO circuit.

junction field effect transistor (JFET) ofthe MPF102 class to serve in the circuitillustrations. In addition, because theNE602 is so popular amongst DCRbuilders I have also included the threeprinciple forms of oscillator circuit usedwith that chip: Hartley, Colpitts andClapp.

Figure 11 shows a Hartley oscillatorcircuit. This type of oscillator is identi-fied by use of a tapped inductor in thefrequency setting network as part of thefeedback network. The source of theJFET is connected to ground through thetap, so its current becomes the feedbacksignal. The top end of the coil is con-nected to the resonating capacitor andthen to the gate of the JFET. Output canbe taken from the drain, gate, or sourceterminals of the JFET, as well as from ei-ther a special tap on L1 or a second wind-ing on the same core as L1. It is commonpractice to use a small value capacitor atthe source terminal for output so as tolightly load the oscillator. The normalideal is to have a capacitance that islarge enough to permit fast startingevery time the circuit is turned on, butsmall enough to not seriously load the LCnetwork.

The tuned circuit that sets operatingfrequency consists of L1 and C1, with L1being tapped for feedback purposes. Inmost cases, the tap is between 20 and 40percent of the total inductance. The cou-pling capacitor between the LC networkand the JFET is a very small value so asto prevent loading. The diode in Fig. 11

is used to provide a limitation on ampli-tude variations. This diode is a small sig-nal silicon diode of the 1N914 or 1N4148class.

Figure 12 shows the Colpitts VFOcircuit. This circuit can be configuredwith a series resonant circuit, in whichcase it is called a Clapp oscillator. Bothtypes of oscillator are identified by thetapped capacitor voltage divider provid-

ing feedback. The oscillating frequency isset by L1 -C1, although the effects of C2,C3 -C4 and the gate capacitance of theJFET must also be considered.

Figure 13 shows a VFO circuit thatuses the transformer core to provide out-put amplitude stability with a low -noiseoperation.12 The inductor, which not onlyhelps control frequency but also limitsamplitude variations, is wound on anAmidon T-68-6 toroidal core. The maincoil (L1) consists of 17 turns of #26 AWGwire, and is tapped at 1 turn for the baseof T1. A feedback coil consists of 2 turnsof the same wire on the same form.

Oscillator stabilityLocal oscillator stability is always impor-tant, but a case can made that it is moreso in DCR receivers. Several factors areinvolved in VFO stability, and if theseguidelines are followed result in a stableoscillator more often than not.13 Someguidelines that will result in a more sta-ble VFO are:

>>.

Avoid excessive temperatures in theoscillator. Also avoid wide variation intemperature.Use only as much feedback as neededto ensure quick starting of the oscilla-tor.Use an output buffer amplifier to iso-late the VFO circuit from changes inthe external load.Use an IC voltage regulator thatserves only the oscillator device (butnot the buffer amplifier).Rigidly mount the frequency determin-ing capacitors and inductors.Prefer air core inductors over ferrite orpowdered iron core inductors; preferslug -tuned coils over toroids.Trimmer and main tuning capacitorsshould be air dielectric types, ratherthan mica or other materials.Small capacitors in the frequency de-termining network, or used as couplingfrom the frequency determining net-work, should be zero temperature coef-ficient types (NPO disk ceramicspreferred).Lightly load the frequency determin-ing LC network by using a small capac-itance (1-10 pF) between the tankcircuit and the gate or base of the oscil-lator transistor.If an air variable capacitor is used forthe main tuning control, then it shouldbe a double bearing model.If a varactor diode is used for the maintuning control, then it should use atuning voltage supply that is regulatedby a varactor controller device such asthe MVS-460-2/ZTK33B.

These guidelines are neither exhaustivenor absolute, but following them asclosely as possible will result in a supe-rior VFO stability.

In the second and final part of this articlewe will look at some practical designs ofdirect conversion receivers.

Notes and references:1. Gary A. Breed, 'A new breed of re-ceiver', QST, January 1988, pp. 16-23.2. The ARRL Handbook for the RadioAmateur - Sixty-fifth edition, AmericanRadio Relay League (Newington, CT,USA, 1988).3. Rick Campbell, KK7B, 'High perfor-mance Direct -Conversion Receivers',QST August 1992, pp. 19-28.4. Roy W. Lewallen, W7EL, 'AnOptimized QRP Transceiver', QSTAugust 1980, pp. 14-19; Paul G. Daulton,K5WMS, 'The explorer: HF Receiver for40 and 80 meters', 73 Amateur RadioToday August 1992, pp.30-34; JohnDillon, WA3RNC, 'The BeophyteReceiver', QST February 1988, pp. 14-18.5. Micheal A. Covington, 'Single -chipFrequency Converter', Radio ElectronicsApril 1990, pp. 49-52; Joseph J. Carr,'NE602 Primer', Elektor ElectronicsJanuary 1992, pp. 20-25.6. Ibid. (Dillon).7. Ibid. (Covington).8. Ibid. (Daulton).9. Ibid. (Campbell).10. S. Niewiadomski, 'Passive AudioFilter Design' Ham Radio September1985, pp. 17-30; cited in Campbell (op-cit.).11. Ray Marston, 'Audio Amplifier ICs',Radio -Electronics. April 1990, pp. 53-57.See also the National SemiconductorLinear Data Books, or the data books ofother major IC manufacturers for appli-cations information and device data.12. From an article by L. Gunn, K7HFD,discussed and cited in W. Hayward andD. DeMaw, Solid -State Design for theRadio Amateur, American Radio RelayLeague (Newington, CT, USA, 1977).13. These criteria were developed fromW. Hayward and D. DeMaw, Solid -StateDesign for the Radio Amateur (op-cit.).



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50

MINI I/O CARD FOR CASIOFX850/880P

A marked difference between large and small computers is the number ofpossibilities available for communication with peripheral devices. In particularpocket-size personal computers, like the Casio FX850/880P, could do with a few

communication extensions. The I/O extension card described in this article adds anRS232 interface and a parallel printer port to the Casio FX850/880 pocket computer.

Design by M. Flinrich (hardware) and G.J. Klasens (software)

OVER the past few decades, calcu-lators have evolved from simple

slide rules to fairly powerful miniaturecomputers. This trend is typified by,among others, the change from a sim-ple one -row LED display on those earlymachines to an extensive graphicsLCD screen on some of the most recentmodels.

Likewise, the possibilities to pro-gram the calculator have gone throughmany changes. Until recently, pro-gramming a calculator was restrictedto typing long strings of primitive cal-culation instructions. What were thencalled advanced machines were capa-ble of storing these instructions on amagnetic tape, which prevented the`program' from being lost when the cal-culator was switched off.

That has all changed with the ar-rival of higher programming languageslike BASIC, Pascal and C. Further, theprograms are now stored in non-volatile memories (usually staticCMOS RAMs). There are even pocketcomputers around with a memory ofmore than 4 MByte.

Not surprisingly, users have an in-creasing need of 'connectivity', i.e,being able to link their pocket com-puter to other equipment, including a'normal' PC. Entering and editing pro-grams using the miniature keyboardon the pocket computer is far less con-venient than on the normal PC.Consequently, many users would liketo have a serial interface that allowsdata to be exchanged between the PCand the pocket computer. Likewise, aprinter port is useful in many cases,particularly if hard copy of calculationresults is required. Fortunately, theCasio FX850/880P has an extensionconnector which has all signals neededto implement a serial and a parallelport.

The circuitThe circuit diagram of the extensioncard, Fig. 1, shows that two gates from

a 4049, IC lc and ICid, are responsiblefor the buffering of the two serial sig-nals, TxD (transmit) and RxD (receive)on the Casio extension connector. Thezener diode connected across the out-put of the TxD driver, IC1c, is a protec-tive device, which starts to conductwhen the output level of the driver be-comes too high, for instance, as a re-sult of a supply voltage increase. Sincethe output stage of the driver containsa resistor, the current through theprotection diodes in the gate is limited,and the voltage level cannot rise above5.6 V. This prevents peripheral equip-ment connected to the computer frombeing damaged. Conversely, resistorR2 ensures that the TxD output isshort-circuit resistant. Furthermore,the current through the zener diode isautomatically limited should the out-put be accidentally connected to theoutput of another device.

The input buffer, ICid, is also pro-tected. Negative voltages at the inputare blocked by diode D2, while resistorR3 serves to establish a 0-V referencelevel. High input voltage levels are

eliminated by the internal protectioncircuit contained in the gates.

The parallel port extension for theprinter consists of a latch, ICs, and sixlogic gates. Gates IC la and IC ib invertthe WE and CS signal respectively,whereupon IC2b combines these sig-nals into a strobe pulse for the latch.The latch serves to store the eightdataline levels needed for the printer.In addition to the data, the printerneeds three control signals: STROBE,BUSY and INIT. Three buffers, IC2a,IC2c and IC2d, enable the PC and theCasio to exchange these signals as re-quired.

ConstructionTo make the construction of the inter-face easier, a printed circuit board wasdesigned. The artwork is given inFig. 2. Unfortunately, this board is notavailable ready-made through ourReaders Services.

Start the construction by fitting thesix wire links, the two sub -D connec-tors (Ki and K2), the pinheader (K3),and the other passive components.Next, mount the diodes and the voltageregulator on to the board, paying dueattention to the polarity of these de-vices. Finally, mount the three digitalICs.

The connector is likely to be a realproblem, because it is, to the authors'knowledge, not available as a standardcomponent. The only way of gettinghold of it is to salvage it from a faultyinterface or another electronic device,or to order it as a spare part. A furtheralternative could be an SMA (surfacemount assembly) connector salvagedfrom a piece of electronic surplus.These connectors usually have thesame raster. Real hobbyists, however,should have a go at making their ownconnector by inserting a number ofstiff wires, or thin needles, into theconnector openings. Next, a smallpiece of thin plastic sheet is insertedbetween the two pin rows for isolation.


MINI I/O CARD FOR CASIO FX850/880P

SERIAL INTERFACE

R2

CEO

D2

14Ot 1N4148

556

rCENTRONICS INTERFACE

I STROBE

K3

1_03_0

02

5-0 6 BUSY

7_0002

RxD 9 10 INIT

11

13_00...LI2

14 TxD

15_0 16 D3/\D4 17 18 D2/\D5 19 20 D1/\D6

21 22 00/\D7 23

0 0

25_0024026

27_0 28 WE

CS 29 30

Num

Casio Connector

WE

CS

2&;& 3

IC2a 5V O

BUSY

IC2c

R1

INIT10

K1IC2d

INIT12

,_, 2513 12_0

BUSY' 11

IC3 10_02 3

00\D7 2

113v 19 D7' 9

\D6 4 17 06' 802L.

\ D5 6 15 05' 70 cgiL.0 oiL.

\D4 8 3 4'

\D3 9 12 DT 50 oiL.

IC1a \D2 7 14 132' 40(:)7_0

\ DI 16 D1' 33 2

0;ji___0 0.15

\0O 3 18 DO'1 0 0144

&STROBE

8 C11nIC1b EN

5IC2b

8...15V

0

!Cie

IC4

7805

100p 505 22p 16V

L

r

74HC573

ICUTxD 7 16

I IC1d

RxD 1009

5V

R3

IC1 IC2 IC3C3

100n

1

1_0

K2.."........

5V

J

I

0 I

I

TxD 2 0 i8

RxD 30 0.20

I

49-0 0-_8_0

IC1 = 4049

IC2 = 74HC08

930090 11

J

Fig. 1. Circuit diagram of the mini I/O interface for the Casio FX850/880P pocket computer.

A few drops of epoxy resin are thensufficient to turn these componentsinto a solid whole.

Once the board is complete and in-serted into the Casio extension con-nector, it is time to connect it to amains adapter (8-15 VDC output), andstart using it.

SoftwareFortunately, the Casio FX850/880Phas built-in software protocols to sup-port communication with peripheralsvia the serial and parallel ports youhave just added. The serial port is de-scribed as COMO in CASIO BASIC. Thecommands that can make use ofCOMO are OPEN, CLOSE, PRINT#,INPUT#, SAVE and LOAD. The para-meters that may be used with thesecommands are listed in the user man-ual.

Diskette 1921 which is availablethrough our Readers Services containsthe program 'Casio", which arrangesthe serial data traffic between a Casiocomputer and an MS-DOS PC. Thisprogram is invaluable for exchangingdata between the Casio and the harddisk in the PC. By virtue of its clearstructure and built-in Help function,the program is readily used, even with-out a manual.

The printer port may be enabled byselecting Mode 7 on the Casio (`enableprinter'). Further, all BASIC instruc-tions that have to do with the printer,like LLIST and LPRINT, make use ofthe parallel port.

Resistors:2 4741 R1;R31 4700 R2

Capacitors:3 100nF C1;C2;C31 10011F 50V radial C41 2211F 16V radial C5

Semiconductors:1 5V6 0.4W zener diode D11 1N4148 D21 4049 1C1

1 74HC08 1C21 74HC573 1C31 7805 1C4

Miscellaneous:1 25 -way sub -D socket,

angled pins, PCB mounting K1

1 9 -way sub -D socket,angled pins, PCB mounting K2

1 30 -way 2 -row pin header K31 Diskette 1921 (see page 70)

Fig. 2. Artwork of the PCB designed for the interface (PCB not available ready-made).


DX TELEVISI N

A two -monthly column by Keith Hamer and Garry Smith

OCTOBER was a vast improvementon the previous month for reception

with a relatively high number of spo-radic -E openings for the same year, withactivity on at least nine days. Signalswere mostly from Spain, Italy andPortugal with strong, stable pictures ofexcellent quality at times.

Towards the end of the month, intensetropospheric activity dominated thescene, producing spectacular DX recep-tion in Band III and at UHF. Signalswere identified from as far away asSpain, Switzerland and Sweden. Bothbands were virtually choc-a-bloc over aperiod of several days; the opening lastedinto the first few days of November. Theremainder of November was fairly mun-dane with only a handful of sporadic -Esignals, mainly from Spain and Portugal.However, an unexpected troposphericopening occurred on the 18th with a del-uge of signals from transmitters as faraway as Poland and Finland.

Reception reportsAndrew Jackson (Birkenhead) com-mented that the tropospheric opening`seemed to go on for ever'. Several 'firsts'were notched up, including a host ofDanish and Swedish transmitters, in ad-dition to several unusual ones from deep-est Germany. The best reception was onNovember 1st and 2nd, with a host ofGerman stations broadcasting test cards,making regional identification relativelyeasy.

On the 27th, Andrew identified trans-missions from the Danish DR network onchannels E7, E10 and E31, plus the TV -2service on channels E22, E26, E27, E30,E35, E40, E48, E56 and E58. During thesame opening, the Swedish transmitterat Halmstad was received on channelE24. All in all, it was quite a remarkablecatch considering that the Pennines werein the reception path! The 28th producedmany unusual German ARD-1 stationsin Band III.

Stephen Michie (Bristol), Garry Smith(Derby) and Tim Tebbs (New Romney) allreport high-level colour signals from var-ious Dutch stations on the 29th. Furtherafield, various German regional broad-casts were identified during the sameopening, including WDR-1, West -3,NDR-1 and MDR -3.

On the 30th, Tim Tebbs receivedGerman transmitters from the SWF pro-

gramme region, notably Haardtkopf(channel E55) and Ahrweiler (E56), andalso their respective ZDF channels.

Several enthusiasts saw the newDutch station `ZH-TV' on channel E49showing colour bars with identification.The station is still undergoing experi-mental tests.

On October 31st, Bob Brooks (SouthWirral), Andrew Jackson, Tim Tebbs andGarry Smith logged many German sta-tions from regions such as WDR-1 onchannels E9 and Ell; West -3 E48 andE55; NDR-1 E11, E43, E50 and E53;NDR-3 E47; WDR-3 E48; RB-1 (RadioBremen) E22; ZDF E21, E26, E34 andE35; MDR -3 E31 (Inselberg). On thesame day, the Swedish TV4 network wasresolved on channel E50 by AndrewJackson.

November 1st and 2nd brought inmany more German stations. AndrewJackson caught Bayerischer Rundfunkshowing the FuBK test card with thetransmitter identification `Dillberg' onchannel E6, and `Buttelberg' on E55.There were also relays of SAT -1 E42,VOX E39, and RTL+ present on channelsE35 and E36. Bob Brooks noted theSwiss test card on channel E6 from thetransmitter atop the Rigi during theopening on the 2nd sporting the `+PTTSRG-1' identification.

The unexpected tropospheric openingon the 18th produced several rarecatches for Simon Hamer (New Radnor).These included Polish TVP-1 signals onchannel R8 from either the Bialystok orKatowice transmitter, plus the YLE-1test card from the Espoo transmitter inFinland on channel E6. This is the firstever report of this transmitter being re-ceived in the United Kingdom. Othergoodies, although Simon has been receiv-ing these fairly regularly, includeNorway's 2nd network on channel E12,and the Swedish 4th network on channelE50.

Keith Greenwell (Luton) identifiedSpanish stations at UHF during the lateOctober tropospherics. During the sameopening, scores of French stations werenoted, including relays of ARTE at UHF.

There were at least four instances oftransatlantic TV reception via sporadic -E throughout the 1993 sporadic -E sea-son, but the precise source of the signals,on channel A2, could not be identified atthe time. Fortunately, Peter Chalkley(Luton) recorded some of his reception,

aim1:011

_num ginFinnish 3rd network FuBK test pattern.Regional identification is sometimesincorporated. The service operates mainly atUHF, but reception in the United Kingdomcould be possible given the rightatmospheric conditions.

and recent examination clearly showsCanadian TV's maple leaf emblem in thebackground of a game show. The likeliesttransmitter is CKCW-TV located atMoncton, New Brunswick with an ERP of56 kW.

Log for October04.10.93: An early afternoon sporadic -Eopening with Spain, Portugal andNorway.07.10.93: Denmark E3; Norway E2 andE4; Italy IA.08.10.93: Italy IA.15.10.93: Denmark E3; Spain TVE-1 E2,E3 and E4; Spain TVE-2 E2; Italy IA;Portugal E3.18.10.93: Netherlands at UHF via tro-pospheric reception.19.10.93: Norway E3; Sweden E3; ItalyIA and IB; CIS R1 and R2; Poland R1;Slovakia R2; Switzerland E2; GermanyE2.20.10.93 - 02.11.93: Tropospheric recep-tion in Band III and at UHF included:Spain, Switzerland, Norway, Sweden,Denmark, France, Germany,Netherlands, Belgium, Luxembourg andEire.

Log for November06.11.93: Sporadic -E signals from Spain,Portugal, Corsica and Italy between 1130and 1400 UTC.18.11.93: Intense tropospheric activityincluded Poland, Finland, Sweden,Norway, Denmark, Germany, Eire,France, Netherlands, Luxembourg andBelgium.

Receiving alternative ITVregionsOver the years, the subject of receivingan alternative ITV region has croppedup, sometimes out of curiosity. For in-stance, in many parts of Derby,Yorkshire TV from Belmont on channel25 is available as an alternative ITV re-gion with good quality colour, but only ahandful of potential viewers realize it.


DX TELEVISION

One problem is, of course, that aerialriggers are reluctant to recommend, orexperiment with, an installation whichmay only produce mediocre or varying re-sults. Despite the technical difficultiesinvolved, most viewers seem to expectperfect results or none at all!

Richard Irving (Holt, Wiltshire) ques-tions the possibility of receiving goodcolour reception from the Crystal Palacetransmitter on channel 23 at his locationeast of Bristol. Unfortunately it is un-likely because under normal receptionconditions, high -power TV signals canonly be successfully received up to ap-proximately 50-60 miles from the trans-mitter.

As DX -TV enthusiasts know, atmos-pheric bending can increase this range,but it all depends on the prevailing con-ditions. With a high -gain aerial and anamplifier, it may be possible to pick upvery weak traces of a signal in excess ofthis distance under 'flat' conditions, butthese would not provide 'entertainment'quality viewing. Only when the signalimproves would this be possible.

In Derby, Channel 4 from the CrystalPalace outlet is detectable, but signalsare very weak and fluttery; turning theaerials to the east produces very weaksignals from the Lopik transmitter in theNetherlands. This is using a standard18 -element Group A aerial raised toabout 10 m, and fitted with a 'Supreme'low -noise amplifier.

When conditions are good, the signalscome up in colour, but reception is unpre-dictable. Signals from

Tyne Tees TV (Bilsdale channel 29),Border TV (Caldbeck channel 28) andAnglia TV (Sandy Heath channel 24)were detectable (in the case of Anglia TV,in colour) before several local relayscame on -air.

For anyone wishing to assess alterna-tive ITV reception at their particular lo-cation, it is best to obtain a copy of atransmitter list such as the handoutssupplied by the BBC, etc., with all fourchannels listed. The closest transmitterwill not always provide the best results.Particular attention should be given toany local topographical features, andalso watch out for local and semi -local re-lays sharing the same group of channels.

If there are signs of an alternative re-gion on the existing aerial, then successmay be assured using a dedicated arrayfitted with an amplifier. For general ex-perimentation, a wideband aerial is aworthwhile choice because it will re-spond to the whole of the UHF spectrum.

Service informationNetherlands: The Nozema has plans foran encrypted pay -TV service on theNED-1 and NED-2 networks during thenight between 0200 and 0700 local time.This will mean that all the Dutch trans-mitters will be on -air 24 hours a day.

Part of the Finnish MTV -3 opening sequence.

Spain: There are changes to the identifi-cation on the GTE test card shown viathe 1st network. Instead of `tve' in largeletters in the upper half of the pattern, astylised '1' inside a rectangular outline isshown.Portugal: The first programme of RTPis now called 'CANAL 1'. The logo in theleft-hand corner is 'Cr with a miniatureglobe inside the letter 'C'. The secondprogramme is called `TV2', and there isalso a logo in the top left-hand corner ofthe picture.

The unidentified transmissions re-ceived on channel E2 this season (withzero offset frequency) originate from anew TV2 transmitter, the ERP and loca-tion of which are, at present, unknown.Czech Republic: All transmitters oper-ating on channel R4 are to be closeddown and transferred to UHF channelR55 by the end of 1994.Germany: A satellite channel dedicatedto travel is due to be launched later thisyear. The broadcasts will be via Eutelsat,and the services will be called 'Reise-TV'(Travel -TV). The broadcasts will origi-nate from outside Germany because theprogrammes are regarded as advertising.

The following information concernsvarious German TV regions:

Bayern: New transmitters assignedfor `Deutsches Sportfernsehen' (DSF) areas follows: Munchen channel E37;Regensburg E38, Neu -Ulm E48; AnsbachE49 and Bamberg E54. A local TV ser-vice called `TV Weil3-blau' (TV White -blue) commenced on 01.09.93 in Munichusing channel E51. Transmissions arebetween 1200-0100, local time. Textpages with local information are shownoutside these times.

Berlin/Brandenburg: The regional ser-vice '1A Brandenburg' commenced lastNovember via the transmitter at Berlin-Alexanderplatz on channel E5 with100 kW ERP.

In Berlin there are several experimen-tal broadcasts currently undergoingtests. On 200 MHz (Band III) and also on107.5 MHz (FM radio band) there is amusic programme using DAB (digitalaudio broadcasting). On channels E47and E49 there are transmissions usingthe new PAL -Plus system; these origi-nate from Alexanderplatz (approx.

500 W), and the SFB Broadcasting House(approx. 5 W).

On channel R59 (400 W) Telekom aretesting four digital TV signals (Videnet)which occupy the bandwidth of only onenormal TV channel. over the comingmonths, there will be many more addi-tional tests emerging.

Mecklenburg-Vorpommern: The fol-lowing transmitters have been assignedfor the first private TV network to oper-ate in the region: Marlow E43; BergenE57; Schwerin E41 and Zussow E55. Alltransmitters have an ERP of 100 kW.

Various companies have applied to op-erate the network. These include Babel-Hilm and Video GmbH, MVTV-RegionalFernseh GmbH i.G.; Pro -7; Rilgen-TV;SAT -1 and Television Mecklenburg-Vorpommern GmbH.

Niedersachen: Telekom has a new TVtower in north-western Hannover. The 1 -kW transmitter on channel E28 is radiat-ing the FuBK test pattern on weekdays.

Hamburg: Channel E34 is assignedfor a new local TV station.Switzerland: The opening of `S -Plus'from Geneva (E38) and Montreux (Mt.Pelerin E52) has been delayed. `TelecineTCR' on channel E96 ceased operation on17.09.93 with `S -Plus' taking over thechannel on the same day.

All three networks come on air at0600 UTC with Euronews, the soundchannel being in French, German orItalian depending on the network. It canalso be heard in Spanish and English byviewers with stereo receivers by switch-ing to the second intercarrier soundchannel as follows:

DRS Net. CH1 in German, CH2 inSpanish;SSR Net. CH1 in French, CH2 inEnglish;TSI Net. Chl in Italian, CH2 inFrench.

However, Euronews is already runninginto financial difficulties with hugelosses incurred for 1993. Most of the fi-nancial resources for the service, whichis also distributed by cable, are believedto come from Swiss banks with the sup-port of SSR and SRG which are bothshareholders.Scandinavia: There are plans to intro-duce a terrestrial channel which can bereceived 'all over Scandinavia'. Tele-X, asit may be known, could be a joint venturebetween Denmark, Norway and Sweden.

This month's service information waskindly supplied by Gosta van der Lindenand the Benelux DX Club, Netherlands;Reflexion, Germany; Pertti Salonen,Finland; Roger Bunney, UK; GarrySmith, UK; Thomas Pahlke, Germany;Bernd Trutenau, Lithuania.

Please send any news about DX -TV inyour part of the world to Keith Hamer, 7Epping Close, Derby DE3 4HR, England.



AMSTRAD DMP4000 Entire printer assemblies includingprinthead, platen, cables, stepper motors etc. Everything bar the electron-ics and case. Good stnpper!! Clearance price just £5 REF: MAG5 or 2for £8 REF: MAG8VIEWDATA SYSTEMS Brandnew units made by TANDATAcomplete with 1200/75 built in modem, infra red remote controlledkeyboard. BT approved, Prestel compatible, Centronice printer port,RGB colour and composite output (works with any TV) complete withpower supply and fully cased. Price is just £20 REF: MAG20 Alsosome customer returned units available at £10 each REF: MAG10PPC MODEM CARDS. These are high spec plug in cards madefor the Amstrad laptop computers. 2400 baud dial up unit completewith leads. Clearance price is £5 REF: MAG5P1INFRA RED REMOTE CONTROLLERSOnginaiiymadetorhi spec satellite equipment but perfect for all sorts of remote controlprojects. Our clearance price is just £2 REF: MAG2TOWERS INTERNATIONAL TRANSISTOR GUIDE. Avery useful book for finding equivalent transistors, leadouts, specsetc. E20 REF: MAG20P1SINCLAIRC6 MOTORS We have a few left without gearboxes.These are 12v DC 3,300 rpm 6"x4', 1/4'OP shaft. £25 REF: MAG25

UNIVERSAL SPEED CONTROLLER KIT Designed by usfor the above motor but suitable for any 12v motor up to 30A.Complete with PCB etc. A heat sink may be required. £17.00REF: MAG17VIDEO SENDER UNIT. Transmits both audio and video signalsfrom either a video camera, video recorder, TV or Computer etc toany standard TV set in a 100' range! (tune TV to a spare channel) 12vDC op. Price isE15 REF: MAG15 12vpsu is£5 extra REF: MAG5P2*FM CORDLESS MICROPHONE Small hand held unit with a500' range! 2 transmit power levels. Reqs PP3 9v battery. Tuneableto any FM receiver. Price is £15 REF: MAG15P1LOW COST WALKIE TALKIES Pair of battery operated unitswith a range of about 200'. Ideal for garden use or as an educationaltoy. Price is £8 a pair REF: MAG 8P1 2 x PP3 req'd.

*MINATURE RADIO TRANSCEIVERS A pair of walkietalkies with a range of up to 2 kilometres in open country. Unitsmeasure 22x52(155mm. Complete with cases and earpieces. 2x PP3req'd. £30.00 pair REF: MAG30 .COMPOSITE VIDEO KIT. Converts composite video intoseparate H sync, V sync, and video. 12v DC operation. £800REF: MAG8P2.LQ3600 PRINTER ASS EM BLIES Made by Amstrad they areentire mechanical printer assemblies including printhead, steppermotors etc etc In fact everything ba r the case and electronics, a goodstripped £5 REF: MAG5P3 or 2 for £8 REF: MAG8P3PHILIPS LASER 2MW helium neon tube. Brand new full spec£40 REF MAG40. Mains power supply kit £20 REF: MAG20P2.Fully built and tested unit £75 REF: MAG 75.SPEAKER WIRE Brown two core, 100 foot hank £2REF: MAG2P1LED PACK of 100 standard red 5mm leds E5 REF' MAG5P4JUG KETTLE ELEMENTS good general purpose heatingelement (about 21(w) ideal for allsorts of heating projects etc. 2 for £3REF: MAG3UNIVERSAL PC POWER SUPPLY complete with flyleads,switch, fan etc. Two types available 150nei at E15 REF:MAG15P2(23x23x23mm) and 200w at £20 REF: MAG20P3 (23x23x23mm)OZONE FRIENDLY LATEX 250m1 bottle of liquid rubber, setsin 2 hours Ideal for mounting PCB's, fixing wires etc £2 each REFMAG2P2*FM TRANSMITTERhoused in a standard working 13A adapted!the bug runs directly off the mains so lasts forever! why pay E700? orpace is £26 REF' MAG26 Transmits to any FM radio.*FM BUG KIT New design with PCB embedded coil for extrastability. Transmits to any FM radio. 9v battery req'd. £5 REF.

MAG5P5FM BUG BUILT AND TESTED superior design to kit, assupplied to detective agencies etc. 9v battery req'd. £14 REF:MAG14TALKING COIN BOX STRIPPER originally made toretail at £79 each, these units are designed to convert and ordinaryphone into a payp hone. The units we have generally have the locksmissing and sometimes broken hinges. Howeverthey can be adaptedfor their original pupose or used for something else?? Price is just £3REF: MAG3P1100 WATT MOSFET PAIR Same spec as 2SK343 and2SJ413(8A,140v,100w) 1 N channel and 1 P channel, E3 apair REF:MAG3P2VELCRO 1 metre length of each side 20mm wide (quick way offixing for temporary jobs etc) £2 REF: MAG2P3MAGNETIC AGITATORS Cosistmg of a cased mains motorwith lead. The motor has two magnets fixed to a rotor that spin roundinside. There are also 2 plastic covered magnets supplied. Made forremotelystining liquids!youmay have a use? £3 each REF: MAG3P32 for E5 REF: MAG5P6TOP QUALITY SPEAKERS Made for HI Fl televisions theseam 10 watt 4R Jap made 4' round with large shielded magnets. Goodquality general purpose speaker. £2 each REF: MAG2P4 or 4 for £6REF: MAG6P2TWEETERS 2' diameter good quality tweeter 140R (would begood with the above speaker) 2 for £2 REF: MAG2P5 or 4 for E3REF: MAG3P4AT KEYBOARDS Made by Ap ricot these quality keyboards needjust a small modification to run on any AT, they work perfectly but youwill have to put up with 1 or 2 foreign keycaps! Price £6 REF.MAG6P3XT KEYBOARDS Mixed types, some returns, some good, someforeign etc but all good for spares! Price is £2 each REF: MAG2P6or 4 for £6 REF: MAG6P4PC CASES Again mixed types so you take a chance next one offthepile£12REF:MAG12 ortwoidenticalonesfor£20REF: MAG20P4component pack bargain 1,000 resistors +1,000 capacitors (allsame value) £250 a pack. REF:MAG2P7

1994 CATALOGUEOUT NOW

MASSIVEWAREHOUSE CLEARANCE

FANTASTIC £20.00 REDUCTION

REFURBISHED PC BASE UNITSCOMPLETE WITH KEYBOARD

FROM ONLY £29.00

AMSTRAD 1512 BASE UNITSGUARANTEED

PERFECT WORKING ORDER.A LOW COST INTRODUCTION TO 1HE HOME COMPUTER MARKET.

AMSTRAD 1512SD1512 BASE UNIT, 5.25" FLOPPY DRIVE ANDKEYBOARD. ALL YOU NEED IS A MONITOR ANDPOWER SUPPLY. WAS £49.00

NOW ONLY £29.00REF: MA G29

AMSTRAD 1512DD1512 BASE UNIT AND KEYBOARD AND TWO5.25" 360K DRIVES . ALL YOU NEED IS A MONITORAND POWER SUPPLY WAS £59.00

NOW ONLY £39.00REF: MAG39

SOLAR POWER PANELS

3FT X 1FT 10WATT GLASS PANELS14.5v/700mA

NOW AVAILABLE BY MAIL ORDER£33.95

(PLUS SZOO SPECIAL PACKAGING CHARGE)

TOP QUALITY AMORPHOUS SILICON CELLS HAVE ALMOST ATIMELESS LIFESPAN WITH AN INFINITE NUMBER OF POSSIBLEAPPLICATIONS, SOME OF WHICH MAY BE CAR BATTERYCHARGING, FOR USE ON BOATS OR CARAVANS, OR ANY-WHERE A PORTABLE 12V SUPPLY IS REQUIRED. REF: MAG34

ALSO 1FT X 1FT GLASS SOLAR PANELS 12v 200mAONLY £15.00. REF: MAG15P3

FREE SOFTWARE!Brand new, UNUSED top quality Fomous brandlicensed software discs. Available in 5.25" DSDD or 5.25"HD only. You buy the disk and it comes with free BRANDNEW UNUSED SOFTWARE. We are actually selling you thefloppy disc for yourown "M EGA CHEAP" storage facilities,if you happen to get software that you want/need/like aswell you get a 'MEGA BARGAIN" tolDSDD PKT10 £2.99 REF: MAG3P7 PKT100 £16.00 REF: MAG16HD PKT10 £3.99 REF: MAG4P3 PKT100 £26.00 REF: MAG26P1

LARGER OANTITY PRICES AVAILABLE ON APPLICATION

iff./£££WE BUY SURPLUS STOCK£££££££TURN YOUR SURPLUS STOCK INTO CASH.

IMMEDIATE SETTLEMENT. WE WILL ALSO QUOTE FORCOMPLETE FACTORY CLEARANCE.

COMING SOON

1994 CATALOGUE.PLEASE SEND 42P , A4 SIZED SAE FOR YOUR FREE COPY

.NIMUM GOODS ORDER 8500 TRADE ORDERS FROM GOVERNI.GENI. SCHOOLS.UNIVERSITIES, &LOCAL AUTHORITIES WELCOME ALI, GOODE SUPPUED SUBJECT TOBUR CONDITION OF SALE AND UNLESS OTHERWISE STATED GUARANTEED FOR 30Ass R OHTS SERVED TO CHANGE PRICES & SPECIFICATIONS WITHOUT PRIOR:'TICE "Tr,' SUBJECI TO STOCK QUOTATIONS WILLINGLY GIVEN FOR QUANTI-

TIES HIGHER THAN THOSE STATED

COMMODORE MICRODRNE SYSTEM mini storagedevice for C64's 4 times faster than disc drives, 10 times fasterthan tapes. Complete unit just £12 REF:MAG12P1

SCHOOL STRIPPERS We have quite a few of the aboveunits which are 'returns' as they are quite comprehensive unitsthey could be used for other projects etc. Let us know how many youneed at just 50p a unit (minimum 10).

HEADPHONES 16P These are ex Virgin Mantic. You can have8 pairs for £2 REF: MAG2P8PROXIMITY SENSORS These are small PCB's with what looklike a source and sensor LED on one end and lots of components onthe rest of the PCB. Complete with fly leads. Pa* of 5£3 REF: MAG:3P5 or 20 for £8 REF: MAG8P4FIBRE OPTIC CABLE Made for Hewlett Packard so pretty goodstuff! you can have any length you want (min5m) first 5m £7 REF:MAG7 thereafter £1 a metre (ie 20m is E22). REF: MAGI Max length250m.

SNOOPERS EAR? Originall made to clip over the earpiece oftelephone to amplify the sound -it also works quite well on the cablerunning along the wall! Price is E5 REF: MAG5P7

DOS PACKS Microsoft version 3.3 or higher complete with allmanuals or price just £5 REF: MAG5P8 Worth it just for the verycomprehensive manual! 5.25' only.DOS PACK Microsoft version 50riginal software but no manualshence only £3 REF: MAG3P6 5.25' only.FOREIGN DOS 3.3-Gennan,French,italian etc £2 a pack withmanual. 5.25' only. REF:MAG2P9MONO VGA MONITOR Made by Amstrad, refurbished E49REF: MAG49

CTM 644 COLOURMONITOR. Made to workwith the CPC464home computer. Standard RGB input so will work with othermachi nes.Refurbished £59.00 REF:MAG59

JUST A SMALL SELCTION of what we have -to see more getour 1994 catalogue (42p stamp) or call in Mon -Sat 9-5.30

HAND HELD TONE DIALLERS Ideal for the control of theResponse 200 and 400 machines. £5 REF:MAG5P9

PIR DETECTOR Made byfamous UK alarm manufacturertheseare hi spec, long range intemal units. 12v operation. Slight marks oncase and unboxed (although brand new) £8 REF: MAG8P5WINDUP SOLAR POWERED RADIO AM/FM radio com-plete with hand charger and solar panel! £14 REF: MAG14P1

COMMODORE 64 Customer returns but ok for spares etc £12REF: MAG12P2 Tested and working units are £69.00 REF: MAG69

COMMODORE 64 TAPE DRIVES Customer returns at £4REF: MAG4P9 Fullytested and working units a re E12 REF: MAG12P5

COMPUTER TERMINALS complete with screen, keyboardand RS232 input/output. Ex equipment. Price is £27 REF: MAG27

MAINS CABLES These are 2 core standard black 2 metre mainscables fitted with a 13A plug on one end, cable the other. Ideal forprojects, low cost manufacturing etc. Pack of 10 forE3 REF: MAG3P8Pack of 100 £20 REF. MAG20P5SURFACE MOUNT STRIPPER Originally made as someform of high frequency amplifier (main chip is a TSA55117 1.3GHzsynthasser ) but good stripper value, an excellent way to play withsurface mount components £1.00 REF. MAGI P1.

MICROWAVE TIMER Electronictimerwith relay output suitableto make enlarger timer etc £4 REF: MAG4P4

PLUG 420? showing your age? pack of 10 with leads for £2 REF,MAG2P 11

MOBILE CAR PHONE £5.99 Weil almost! complete in carphone excluding the box of electronics normally hidden under seat.Can be made to illuminate with 12v also has built in light sensor sodisplay only illumi nates w hen dark. Totally convincing! REF: MAG6P6

ALARM BEACONS Zenon strobe made to mount on an externalbell box but could be used for caravans etc. 12v operation. Justconnect up and it flashes regularly) E5 REF: MAG5P11

FIRE ALARM CONTROL PANEL High quality metal casedalarm panel 350x165x80mm. Comes with electronics but no informa-tion. E15 REF: MAG15P4

SUPER SIZE HEATSINK Superb quality aluminium heatsink.365 x 183 x 61mm, 15 fins enamble high heat dissipation. No hdes!£9.99 REF: MAG10P1PREMOTE CONTROL PCB These are receiver boards forgarage door opening systems. You may have another use? E4 eaREF: MAG4P5

LOPTX Line output transformers believed to be for hi res colourmonitors but useful for getting high voltages from low ones! £2 eachREF: MAG2P12 bumper pack of 10 for £12 REF- MAG12P3.

'SOME OF OUR PRODUCTS MAY BE UNLICENSABLE IN THE UK

BULL ELECTRICAL250 PORTI.AND ROAD HOVE SUSSEX

BN3 5QTMAIL CORDER TERMS: CASH POOR CHEQUEWITH ofoeR PLUS elvo POST PLUS VAT.

PLEASE ALLOW 7 ,10 DAYS FOR DELIVERYTELLPHONE ORDERS WELCOME

Tag 027320350X/

FAX 0273 373.077

PORTABLE RADIATION DETECTOR

£49.99A Hand held personal Gamma and XRay detector. This unit contains twoGeiger Tubes, has a 4 digit LCD dis-play with a Piezo speaker, giving anaudio visual indication. The unit de-tects high energy electromagneticquanta with an energy from 30 K eV toover 1.2M eV and a measuring rangeof 5-9999 UR/h or 10-99990 Nr/h. Sup-plied complete with handbook.

REF: MAG50



33NAJ-1113VIIU8SURVEILLANCE

A SMALL SAMPLE OF OUR RANGE KIT MODULE PROFFINISHED

ROOM TRANSMITTER RT1 An extremelysensitive miniature transmitter with long battery life.

9.95 13.75 19.00

Dimensions: 20 x 20mm

MAINS TRANSMITTER MT4 Can be connectedinside any equipment that is mains powered.

19.75 31.50 46.00

Dimensions 35 x 20mm

TELEPHONE TRANSMITTER TTS Small enoughto conceal within a telephone. Will transmit both sides ofa conversation (series connection)

12.75 17.50 25.00


TELEPHONE SOCKET TRANSMITTER TSTS 14.74 29.00Replace your telephone socket with this one withinwhich a transmitter has been concealed.

ROOM AND TELEPHONE TRANSMITTER RTT 31.50 45.50 86.00Operates as a room transmitter, then switches totelephone transmitter mode during telephone calls.Dimensions: 30 x 25mm

AUTOMATIC TELEPHONE RECORDER 16.80 25.90 39.00SWITCH TRS2 Record telephone conversations withthis interface unit and your own tape recorder.Dimensions: 36 x 50mm

AUTOMATIC TELEPHONE RECORDER ATR1 34.95 69.00Adapt the tape recorder included to record telephonecalls automatically.

TELEPHONE TAP ALERT TTA1 Visual warningof any invasions of privacy on your telephone line.

21.95 31.50 45.00


RF DETECTOR RFD1 Highly sensitive hand-helddetector. Range between 10Mhz and 600Mhz. Silentoperation. Dimensions: 70 x 50mm

42.75 69.00 95.00

CAMERA DETECTOR CD8 Detects hidden videocameras (even miniature CCD models).

69.00 89.00 125.00


RECORDING BRIEFCASE RBC1 completelydiscreet recordings at a value for money price.

1.1 145.00

SHOTGUN MICROPHONE AMPLIFIER SMA 24.95 36.00 4500Ideal for surveillance. The amplifier will pick up soundsfrom a long distance.

SIGNALLING TRANSMITTER SIGT Sends acontinual audio pulse. Can be integrated into alarm,tracking or warning systems. Dimensions, 20 x 50mm

21 95 34.89 45.00

TELEPHONE AMPLIFIER TA5 Connected directlyto the telephone, this unit will amplify both sides of atelephone call. Dimensions: 25 x 52mm

10.95 16.95 19.95

PROFESSIONAL SOUND TO LIGHT UNIT 21.95 32.49 44.95SK72 Custom built for disco or home use. Audio signaldivided into bass, mid and treble bands, with internalmicrophone and spotlight option.Dimensions 210 x 45mm

MICRO METAL DETECTOR MMD Detect thepresence of ferrous and various non-ferrous metals.

9.95 16.95

Useful for all those DIY jobs. Dimensions: 40 x 25mm

Please add £2.00 P & P to all orders and 17.5% VAT on all U.K. orders,

For full catalogue please send two 1st class stamps or 2 IRC'S

. : II

S

MEASUREMENT DATA ACQUISITION & CONTROL BOARDSAR -B3001 16 Channel, 12Bit ND Card £66AR -83201 8 Channel 12Bit A/D + 3 Channel D/A Card £96AR -83204 16 Channel, 12Bit, Data Acquisition & Control Card, Programmable Gain £235PCL-711B 8 Channel, 12Bit, Data Acquisition & Control Card, Programmable Gain £185PCL-812-PG 16 Channel, 12Bit, Data Acquisition & Control Card, Programmable Gain £306PCL-813 32 Channel, 12Bit, Data Acquisition Card £347PCL-818H High Performance 16 Chanel, 12Bit Data Acquisition & Control Card £472PCL-814 Modular Multifunction 16 Channel, 14Bit, Data Acquisition & Control Card £680PCL-816 Modular Multifunction 16 Channel, 16Bit, Data Acquisition & Control Card £964PCL-860 4 1/2 Digit Voltmeter (DCV/ACV/DCR) Card £369AR -B2001 16 Channel Opto-Isolated Digital I/P Card £52AR -B2102 16 Channel SPST Relay Switch Card £74AR -82201 64 Channel Digital I/O Card £41AR -B9221 3 Port (24 Bit) Digital I/O, 3 Chan Counter/Timer, Prototype Card £41AR -B9101 16 Channel SSR Switching Card (For AR -89221) £242PCL-720 32 Channel Digital I/P + 32 Channel 0/P, 3 Channel Timer/Counter £128PCL-722 144 Bits (24'6) of Buffered Digital I/O £250PCL-724 24 Bit Digital I/O Card £77PCL-725 8 Channel Relay + 8 Channel Isolated Digital I/P £167PCL-726 6 Channel 12 Bit D/A Output Card (16 Channel Digital I/P + 16 Channel DIP) £389PCL-838 Stepper Motor Control (3 Motors), 16 Channel D/IP + 16 Channel D/OP £319PCL-750 Prototype Development Card £66PCL-755A Slot Extension Card (XT/AT) £41PCL-756 PC -Bus 8 Bit Switch/Extension Card £125PCX-794 PC/XT BUS Expansion System (Master + Slave Cards + 1m Cable) £211PCL-830 10 Channels of 16Bit Counter Timer (AMD9513 ' 2) £ 204

SIGNAL CONDITIONING/CONTROL DAUGHTER BOARDS (For use with PCL cards)PCLD-782 Opto Isolated Digital I/P (16 Channel) £132PCLD-785 16 Channel Relay 0/P Board £153PCLD-787 8 Channel Sample & Hold Card £361PCLD-788 Relay Scanner/Multiplexer Board £195PCLD-779 8 Channel Isolated Relay Mux and Amplifier Board £264PCLD-789 Amplifier & Multiplexer Board £243

COMMUNICATIONS & INTERFACE BOARDS (RS232/RS422/RS423/11S485/IEEE-488)1-104 4 Port Serial RS232 PC Card £59PCL-743 Dual Port RS422/485 PC Interface Card £98PCL-744 Intelligent 8 Port RS232 PC Interface Card with on -board CPU £410AR -89011 Dual Port RS422/485 PC Interface Card £66PC -232-485 RS232-RS485 or (232-422) Converter Adaptor, Self Powered £65PCL-848A IEEE -488 Interface Board £222

ADAM REMOTE/DISTRIBUTED MODULAR DATA ACQUISITION MODULESADAM -4011 Analogue Input Module (mV, V, mA, Thermocouple) £154ADAM -4021 Analogue Output Module (V or mA) £154ADAM -4050 Digital Input/Output Module £112ADAM -4060 Relay Output Module £112ADAM -4520 Isolated RS-232/RS-485 Converter Module £84

19" RACK MOUNTING MULTI -SLOT INDUSTRIAL PC CHASSISAR-IPC12A Industrial 19' Rack Mounting Chassis, 12 Slot, 200W PSU £454AR-IPC12M Industrial 19" Rack Mounting Chassis, Motherboard fitting, 200W PSU £396IPC-610A Industrial 19" Rack Mounting ChasSis,14 Slots, 250W PSU £718IPC-610MB Industrial 19" Rack Mounting Chassis, Motherboard fitting, 250W PSU £644IPC-6520 19" Rack Mount Monitor Kit for 14" Monitor £352IPC-6305 19" Rack Mount Keyboard & Drawer, Telescopic Slides £279

PC -BUS CARD CHASSIS FOR CUSTOM ENCLOSURES/EMBEDDED APPLICATIONIPC-6706 PC -Bus Card Cage Enclosure Chassis (With 6 Slot Passive Backplane) £176IPC-6806 6 Slot Node IPC Chassis, 150W PSU, Floppy + Hard Disk Mountings £410AR-IPC6MP 6 Slot Node IPC Chassis, 200W PSU, Floppy + Hard Disk Mountings £290MBPC-640 Micro Box Industrial PC Chassis (With 3 Slot Backplane) £135PCXU-205 PC BUS Expansion Unit (With 5 Slot Backplane & Power Supply) £176IPC-6010 8 Slot Passive Backplane Card Cage (6'16 + 2'8 Bit), card clamp, speaker £132AR-CC6LP 6 Slot (16 Bit) Passive Backplane Card Cage, Full Length, 150W PSU £227AR-CC11LP 11 Slot (16 Bit) Passive Backplane Card Cage, Full Length, 150W PSU £246

SOLID STATE FLASH/SRAM/ROM DISK CARDSAR -B7008 512K ROM or 256K SRAM Disk Card £80AR -B7010 512K ROM Disk Card. £59AR -B7040 4MB Flash/SRAM/ROM Disk Card. £118PCD-890 12MB Flash/SRAM/ROM Disk Card. Dual Floppy Emulator £200PCD-8928 6MB Flash/ROM Disk Card £118

Plus MUCH more ...Please CA LL for your FREE copy of our latest Catalogue

OEM, Dealer & Educatcand/ folk/ries Welcomer

n INTEqRATEd Integrated Measurement Systems Ltd.A,305-308 Solent Business Centre, Millbrook Rd West..'MEASUREMENT Southampton S01 OHW, HAMPSHIRE

SYSTEMS Tel: (0703) 771143 Fax: (0703) 704301Designers & Suppliers of Measurement, Test & Control Systems & Software


56

ELECTRONIC FUSEWe tend to forget about fuses until one has blown, when it istime to locate and investigate an electrical overload problem.Once that is fixed, a new fuse must be installed. Typically, thiswill not be handy at the required rating, and the shops areclosed. What a drag to serious experimenting! Fortunately,these problems can be overcome with the present circuit. Thefuse described here never needs to be replaced, and is asgood as new any time the reset switch is pressed.

Design by K. Walraven

MHE little circuit described in this1 article is the electronic version of

the well-known glass fuse, which meltswhen it carries a current exceeding its`A' (ampere) specification. By melting,the wire in the fuse interrupts the cur-rent flow in the circuit, and so protectsan electrical device against damagecaused by overheating. Unfortunately,the common wire fuse (usually con-tained in a small glass tube with metalend caps) is not re -usable, and has tobe replaced with a new one every timean overload condition occurs.Obviously, this is annoying whenfaultfinding in equipment, or experi-

menting with a circuit whose maxi-mum current drain is not accuratelyknown yet. Ideally, a fuse would haveto be resettable, and, you guessed it,that is a feature par excellence of thepresent circuit.

How it worksAs shown in Fig. 1, the circuit consistsof little more than two transistors andone thyristor. The electronic fuse is in-serted into the supply line of theequipment to be protected. The cur-rent at which the circuit is actuated isdefined with the aid of a single resis-

Fig. 1. circuit diagram of the electronic fuse. The fuse actuation level is determined by thevalue of resistor R3. Once actuated by an overload condition, the fuse can be reset by press-ing S1 (a push -to -break contact).

tor, R3, which is connected as an ex-ternal part to connector K3.

The operation of the circuit is sim-ple. Darlington transistor T2 functionsas a current -controlled switch, its col-lector -emitter junction carrying thecurrent flowing into the load con-nected to K2. Since T1 feeds a currentinto the base of T2, the 'switch' is nor-mally closed, and the load powered. T1functions as a current source, with thebase of the transistor held at a con-stant voltage by LED D 1. Conse-quently, the emitter resistor of R2 willsupply a constant voltage, which, inturn, results in a constant emitter cur-rent (and collector current), of whichthe magnitude is determined by thevalue of R2. Here, the constant currentis just over 10 mA, which is ample tokeep T2 conducting.

The load current also flows throughresistor R3. As soon as the currentrises to a value that causes a voltagedrop of about 0.6 V across R3, thyris-tor Thi starts to conduct. This causesthe base of T2 to be pulled to theground line of the power supply.Consequently, T2 is switched off, andbreaks the current flow to the load.The current remains broken becausethe current supplied by T1 is a littleabove the 'hold' level of the thyristor.The current is interrupted the momentswitch Si is pressed, when Thi isswitched off. That is, if the load cur-rent has dropped below the criticalvalue. If not, the thyristor will start toconduct again.

The fuse valueThe current level at which the elec-tronic fuse is actuated is simple to cal-culate using Ohm's law. As already


ELECTRONIC FUSE

Fig. 2. The fuse actuation current can bemade variable by connecting a fixed resistorand a potentiometer in series on connectorK3.

mentioned, the fuse is actuated at avoltage of 0.6 V across R3. Therefore,the fuse comes into action at a currentof 600 mA (0.6 A) with R3 = 1 S2.

Similarly, the actuation current is125 mA with R3 = 4.7 S-2, or 50 mA withR3 = 12 IL

Looking at the most commonly usedlow -power fuse values, the value of R3will usually lie between 1.2 S2 and12 S2. The minimum value that may beused is 0.68 S2, which results in a 'trip'value of 1 A. That corresponds to themaximum current this circuit canhandle safely.

Assuming that the electronic fuse isbuilt into a power supply for use inyour workshop, it is, of course, usefulto make the current limiting actionswitchable or continuously variable.The former is achieved by fitting a ro-tary switch and a number of resistors.A continuously variable fuse actuationlevel is implemented by connecting apotentiometer in series with R3. Note,however, that most ordinary pots canwithstand a dissipation of about onewatt only. Relatively high currentstherefore call for a wirewound poten-tiometer. The resistor/potentiometer

9

Resistors:R1 = 4417R2 = 6852R3 = see text

Capacitors:D1 = red LEDT1 = BD140T2 = DB679Th1 = TIC106

Miscellaneous:K1;K2;K3 = 2 -way PCB terminal block;raster 5mmS1 = push -to -break button

combinations shown in Fig. 2 are in-tended as suggestions to help you onthe way.

Finally, still on component values,be sure to use a power resistor in posi-tion R3 at currents exceeding 500 mA.

Construction andpractical useConsisting of an absolute minimumnumber of components, the electronicfuse should be a simple constructionproject for anyone with a basic knowl-edge of electronics. The less experi-enced constructors among you will bepleased to know that artwork is avail-able to make a printed circuit boardfor the present project - see Fig. 3.Unfortunately this printed circuitboard is not available ready-madethrough the Readers Services.

When connecting the electronicfuse, keep in mind that it introduces avoltage loss in the supply line to theload to be protected. As already men-tioned, a voltage drop is introduced by

Pire14-O_+e eK3 KI

ruOpel b ccThi TiO 000O 000

s7 T2

Fig. 3. Track layout and component mounting plan of the printed circuit board designedfor the electronic fuse (PCB not availableready-made).

R3, but also by the collector -emitterjunction of the conducting darlingtontransistor, T2 (approx. 1 V). In mostcases, this will not be a problem, butyou are well advised to take the dropinto account when the circuit is usedto protect a load which operates at lowvoltages.

Fig. 4. Completed prototype with external current -determining resistor and potentiometer fit-ted to K3.

4)1


58

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Overdriven amp with highly inductive Ikrid I'Harmariles In kid current from ricrerdrivm

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Books from Elektor Electronics (Publishing)

The following books are currently available: see order form on p. 79) or direct from our Dorchester

301 Circuits £9.95 $14.50 office (private customers only*) on the order form on page

302 Circuits £9.95 $14.50 79.

303 Circuits £10.95 $17.90 * Orders other than from private customers, for instance,

304 Circuits £12.95 $23.95 bookshops, schools, colleges, should be sent to

305 Circuitst £14.95 $27.70 Gazelle Book Services Ltd

SMT Projects £ 9.95 $14.50 Falcon HouseMicroprocessor Data Book £10.95 $19.90 Queen SquareData Sheet Book 2 £9.95 $18.50 Lancaster LA1 1RNData Book 3: Peripheral Chips £10.95 $19.95 EnglandData Book 4: Peripheral Chips £10.95 $19.95 Telephone (0524) 68765; Fax (0524) 63232

Data Book 5: Application Notes £10-95 $19.95

The books may be obtained from bookshops*, Old ColonySound Lab (USA and Canadian readers only-for address,

t We regret that, owing to technical difficulties beyond ourcontrol, publication of this book hass been delayed to theend of March 1994.



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60

CAR BATTERY VOLTAGE MONITOR

Itis particularly during the autumn and

winter months, when a car battery iscalled upon to provide a lot of energy, thatmore is sometimes taken from it than putback. The inevitable result is a flat bat-tery. Moreover, during these wetter monthsa battery is required to be in tip-top con-dition to be able to cope with condensa-tion on the sparking plugs. Problems mayarise in the warmer months as well, how-ever. It may happen, for instance, that thevoltage regulator, the alternator (or, in oldcars, the dynamo) or the rectifiers arefaulty. Such a fault may result in muchtoo high a charging voltage, which se-verely lowers the life of the battery, or toolow a charging voltage so that the batteryis hardly charged. In all these cases, abattery voltage monitor is indispensable.

The monitor described in this articleuses three LEDs: green to show that allis well, red to indicate that the chargingvoltage is too high, and yellow to showthat the charging voltage is too low.

The circuit in Fig. 1 may be built on apiece of prototyping board or on the DIYprinted -circuit board shown in Fig. 3. Inthe latter case, the board may be builtinto a car -type cigarette lighter.

Circuit descriptionThe circuit (Fig. 1) is a fairly simple de-sign based on a window comparator, IC1.A window comparator consists of two sep-arate comparators, each of which moni-tors whether its input signal is below orabove a level preset by the user. The com-bination of two comparators enables twodifferent levels to be monitored simulta-neously. It can, therefore, indicate whetheran input signal is lower or higher thanthe two threshold levels, or whether thesignal lies between the two, that is, withinthe so-called window. This is exactly whatis needed for the present monitor, sincethis must show whether the battery volt-age is too low, too high, or just right (withinthe window).

The upper and lower threshold levelsare determined by potential divider R3 -R5.The potential at pin 10 of IC1 is a con-stant 6 V, derived from a regulator onboard IC1. The values of R3 -R5 have beenchosen to give a voltage at junction R3 -R4of 3.6 V and one of 2.9 Vat junction R4 -R5.This means that the window ranges from2.9 V to 3.6 V.

The input voltage is derived from thebattery via potential divider R1 -R2 and isapplied to pin 8 of IC 1. The potential atjunctionR -R2 is exactly a quarter of thebattery voltage. Thus, if the battery volt-age is 12 V, the input signal at pin 8 is

Design by L. Pijpers

If you have ever tried to start your car and found the battery (al-most) as flat as a pancake, you will appreciate this miniaturemonitor, which fits in the car's cigarette lighter Its LED indica-tors tell you when the battery voltage drops dangerously low

and also when the charging voltage is too high.

3 V. This level falls within the window andis, therefore, considered to be good.

From the ratio R1 : R2, it follows thatthe battery voltage is all right if it is be-tween 11.6 V and 14.4 V. Below 11.6 V itis too low and above 14.4 V it is too high.

To ensure that the monitor does notfollow any variation in the battery volt-age, the circuit is designed to react onlyto slow variations. Low-pass filter R1 -C1suppresses any fast changes, such asthose caused by the car's ignition system,for instance. Such peaks are short-cir-cuited to earth by C1.

Depending on the input signal, one ofthe three LEDs at the output of ICI lights:the green one (D2) when the battery volt-age is between 11.6 V and 14.4 V; the yel-low one (D1) when the voltage is too low;and the red one (D3) when the voltage istoo high.

Apart from low-pass filter R1 -C1, thecircuit has another facility that preventstoo rapid switching between LEDs: hys-teresis. This is set by potential dividerR6 -R7, which has a ratio of 1 : 100. Thus,the potential of 6 V at pin 10 is broughtdown to 60 mV at pin 9. The hysteresis

is exactly twice this value, i.e., 120 mV.This means that only variations in bat-tery voltage greater than 120 mV cancause a switch from one LED to another.

ConstructionAlthough the design is aimed at keepingthe unit as small as possible, as shownby the printed -circuit in Fig. 3 (not avail-able ready made), it is, of course, not nec-essary to make it that small, in whichcase it may be constructed on a suitablepiece of prototyping board. If the moni-tor is constructed on the PCB, it can bebuilt into a cigarette -lighter plug.

Note that C1, R 1 , R4 and IC1 are fittedon to the board as shown in Fig. 4. Keepthe terminals of all these components asshort as feasible to prevent short-circuits.

Cut the terminals of the three flat LEDsto a length of about 5 mm. and solder thediodes to the board as shown in Fig. 4and Fig. 5.

Next, solder the remaining resistors tothe track side of the board as in Fig. 5:start with Rg. Here again, cut the termi-nals of these components as short as fea-


CAR BATTERY VOLTAGE MONITOR 61

GND

BELOW

OUTSIDE

INN A

V REF

U LIMIT

L LIMIT

V REF

U LIMIT INSIDE

L LIMITW CENTER

BELOWH WINDOW

INH B OUTSIDE

INH A .1.

Fig. 1. Circuit diagram of the car battery voltage monitor

TCA965

ABOVE

INSIDE

INH B

V STAB

H WINDOW

W CENTER

926122X - 12

Fig. 2. Pinout of IC1.

atKl;,\N:#7`04i,N.k

rir fp\

L.4? -/-45-130 7c7cly_b2e'

Fig. 3. The PCB for the monitoris not available ready made

sible. Solder R6 and R3 in place last. Becareful not to cause a short-circuit whensoldering R3 'around' R6. Some sleevingaround its terminals will help. The riskof a short-circuit is greatest near pin 6 ofIC1 and between pins 10 and 11 of the IC.

When all components have been fit-ted, carry out a thorough visual inspec-tion. When this is satisfactory, connect avariable power source (0-20 V) to theboard. Increase the voltage slowly from0 V to 20 V when first the yellow, thenthe green and finally the red LED shouldlight. If this test is satisfactory, the boardcan be built into the cigarette lighter plug.

Great care has to be taken to preventshort-circuits caused by shifting compo-nents. It may be necessary to bend themetal clip slightly outwards so that it fitsneatly around the IC. It is recommendedto wrap some insulating tape around theclip and earth it with a short length ofwire.

If the monitor has been constructedon a prototyping board, the same visualinspection and electrical test should becarried out, after which the unit may befitted in a suitable small enclosure.

The current drawn by the monitor de-pends to large extent on the battery volt-age: it is about 10 mA at 5 V, 30 mA at12 V and 40 mA at 20 V.

The threshold voltages can be alteredby changing the values of R3 -R5. The po-tential at junction R4 -R5 is R5/ (R3+R4+R5)times 6 V. That at junction R3 -R4 is(R4+R5)/(R3+R4+R5) times 6 V. The win-dow may be moved up or down by alter-ing the scale factor R2/(R1+R2). With valuesspecified for the present design it is 1/4.Some constructors may find it desirableto use 1% resistors here also.

Parts listResistors:R1 = 82 'cc -2R2 = 27 ki2R3 = 4.32 kS2, 1%R4 = 1.371d2, 1%R5 = 5.49 kS2, 1%R6 = 10 kS2R7 = 100 C2R8 = 560 12

Fig. 4. Completed PCB (component layout side) Capacitors:C1 = 4.7 jt F, 10 V, tantalum

Semiconductors:D1 = LED, yellow, flatD2 = LED, green, flatD3 = LED, red, flat

Integrated circuits:IC1 = TCA965

Miscellaneous:1 off car -type cigarette lighter plug

Fig. 5. Completed PCB (track side)


62

BUILDING ELECTRONIC CIRCUITS

Although ready-made printed circuit boards are available formost projects described in this magazine, there are caseswhere a 'real' PCB is not necessary. For instance, with small-scale experiments, or if the design is simply not critical asregards component layout. In such cases, prototyping board(also called stripboard or veroboard) is a very useful, easy tohandle, alternative.

By our design staff

A S many of you will be aware, aAScircuit board is a key ele-

ment in almost any electronics con-struction project, since it ensurescompactness, reliability and safety.Unfortunately, making a printed cir-cuit board for a particular circuit isoften more difficult and time consum-ing than actually building the project,i.e., soldering and wiring. None theless, printed circuit boards are pro-duced at home or in the hobbyist'sworkshop by skilful experimenters whoare not daunted by the amount ofwork, which is mostly chemistry andphotography.

After etching and cleaning, theprinted circuit board is drilled using asuitable drilling machine. Next, thecopper tracks are smoothed with apiece of wire wool, and then sprayedwith solder lacquer to give them a pro-tective coating. Optionally, a compo-nent layout is printed on thecomponent side of the board.

As already mentioned, making one'sown printed circuit boards is time con-suming and certainly not easy, and not

everyone will have the time and meansnecessary to achieve satisfying results.

If a certain printed circuit board isnot available ready-made, or if no art-work is provided, construction on pro-totyping board should be considered.On prototyping board, components aresoldered at the desired locations, andthen interconnected using shortlengths of enamelled copper wire,which run at the solder side. Thismethod is well -proven, if only by thefact that nearly all circuits described inthis magazine are built in this way byElektor Electronics design staff before aprinted circuit board layout is drawn.

The circuit diagramConstruction on a prototyping board isbest illustrated with the aid of a practi-cal example, in this case, building asimple generator.

Figure 1 shows the circuit diagramof a sine -wave generator which pro-duces a fairly clean 1 -kHz tone. Theoutput level is adjusted with preset Pi.This tone generator is ideal if you want

to test and adjust audio circuits, butdo not have a full-blown function gen-erator. Since our main concern in thepresent article is the construction of atone generator, a description of its op-eration is not given.

First, let us have a look at the toolsand materials needed to build the cir-cuit on prototyping board.

Tools and materialsFortunately, the tools and materialsneeded to build a circuit on prototyp-ing board are fairly common, and willbe found even in the 'poor man's' work-shop.

The materials shown in Fig. 2 in-clude a small piece of prototypingboard cut to size. The connections be-tween the components on the boardare made in 0.2 mm dia (SWG36)enamelled copper wire. Note that thisdiameter is given as guidance only -connections carrying large currentsshould be made in thicker wire. Alsoneeded is a soldering iron with a powerrating of about 30 W. Obviously, thereis nothing against using a tempera-ture -controlled soldering station withadjustable solder temperature (350-400 °C). The relatively high solder tem-perature is needed, among others, tomake the enamel lacquer coating at thewire ends melt, so that the copper wirecan be tinned and soldered.

A sponge and a plastic flask con-taining a little water should be kepthandy to enable the tip of the solderiron to be cleaned from time to time.The flask saves you having to walk to atap every half hour or so to moisten thesponge. Several types of small flask orbottle may be used. The flask shown inFig. 2 used to contain contact lenscleaning/storage liquid, and was cho-sen because of its nozzle and solidsealing cap.

Furthermore, you need flat nose pli-ers, solder tin (type 40/60 alloy), PCBsolder pins and, of course, the compo-nents that make up the circuit.

A component lead preforming aid isuseful, but not indispensable. Thesame goes, basically, for a circuitboard holder that can be used duringthe testing phase also. Finally, beforeyou start soldering, make a copy of thecircuit diagram on paper, and have acolour felt pen handy. Enlarge the dia-gram if it is complex.

Practical constructionAlthough the example circuit works ata voltage which is quite safe to touch,


BUILDING ELECTRONIC CIRCUITS 63

Fig. 1. The example circuit discussed in thisarticle is a simple sine -wave oscillator.Always useful as a signal source for testingaudio circuits!

it is always useful to bear in mind therequirements for electrical safety whendealing with higher voltages, such asthe mains. Wherever the mains voltage(240 V) is present on a printed circuitboard, a minimum isolation distance of6 mm should be observed between sol-der points. On prototyping board, thisis easily achieved by removing all cop-per spots within a distance of 6 mm of,for instance, the spots to which the pri-mary terminals of a PCB -mount mainstransformer are soldered. The spots tobe removed are firmly heated with thesolder iron. The heat partly melts the

MP

glue between the spot and the boardmaterial, and will cause the spot tocome loose (Fig. 3), so that it can bepicked up with the tip of the iron, orsimply pushed off the board surface.

Start the construction by fitting thepart with the highest number of termi-nals, or the largest size. This is done toprevent lack of space for this compo-nent later. For small parts, it is mucheasier to find a place if you find thatone or two have been overlooked.

Transistor T1 is selected as the cen-tral part in the sine wave oscillator,and it is fitted first, observing the sizeof preset P1. Next, fit capacitor C3 sothat one of its terminals is close to thebase of Ti (see Fig. 4). Next, bend thecapacitor terminal to the transistorbase terminal, and join the two by sol-dering (Fig. 5). Mark this connection inthe circuit diagram by running the feltpen over the relevant line in the draw-ing (Fig. 6). Make a habit of markingthe interconnections in this way imme-diately after soldering - it may saveyou a lot of trouble later.

Next, fit preset P1 in the vicinity ofthe emitter of T1. The connection be-tween the emitter and the preset ismade using a short piece of copperwire. Make sure the solder iron is hot,apply some fresh solder tin to the tip,and then pre -tin the end of the enam-elled copper wire which is still on thereel. Clean the solder tip by wiping itacross the sponge - this is necessarybecause most of the solder resin willhave evaporated at the high tempera-ture. Do not cut off the wire as yet -

Fig. 2. Most of the tools necessary for working with prototyping board will be available in yourtoolcase. A water flask, a component wire preforming tool and a circuit board holder are op-tional to make construction easier.

Resistors:R1;R2;R3 = 39141R4 =R5 = 2kS27P1 = 21625 preset

Capacitors:C1;C2;C3 = 10nFC4 = 100p.F 10\/

Semiconductors:T1;T2 = BC54713

Fig. 3. All copper spots within 6 mm distanceof a terminal at mains potential should be re-moved. This is readily achieved by heatingspots with the solder iron, and then pushingthem off the board.

Fig. 4. Lack of space on a circuit board spacemay be avoided by first fitting the larger com-ponents. Since the connections are madewith wires, the constructor is free to deter-mine the position of the parts on the board(within limits, of course). Evidently, parts thatare interconnected are mounted as close aspossible to one another.

a.

40 4041

41

Fig. 5. Here, you do not need a wire. The con-nection between capacitor C3 and the baseof transistor T1 consists of a bent terminal ofcapacitor C3.


64 GENERAL INTEREST

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that would leave you with a short wirewhich is difficult to handle.

Solder the wire end to the emitter orthe preset terminal. Next, run the wireto the other point to be connected, cut,and pre -tin the end. Clean the solderiron tip, apply fresh solder tin, and jointhe wire to the solder spot (Fig. 7).Mark the connection you have justmade in the circuit diagram (Fig. 8). In

Fig. 6. The 'prototyping board' method worksonly if the connections made by solderingare consistently marked in (a copy of) the cir-cuit diagram.

r\/ MultichannelFree view

_No contracts

SmartCardD2 -Mac Eurocrypt

VideocryptIK-Tjanst

P.O. Box 460S-901 09 Umea, SwedenPhone + 46 (0)90 13 84 40

Fax + 46 (0)90 13 84 70BBS + 46 (0)90 13 84 70

at ** ........ * ......

* .. * * ....... *..... . a # . 4.4.

. .

Fig. 7. Example of an interconnection madein enamelled copper wire at the solder side ofthe board. Thanks to the isolation formed bya thin enamel coating, wires are allowed tocross freely without affecting the operation ofthe circuit.

this way, all components are fitted onto the board, and interconnected as in-dicated by the circuit diagram. Theconnections with the 'outside world'(battery connections and signal out-put) are best made with the aid of sol-der terminals.

If there are no more components left(inspect the floor or the carpet also!),examine the circuit diagram copy tosee if all interconnections have beenmarked. If this is the case, you may

reasonably expect the circuit to workspot-on. A careful last check on allconnections and component polarities(where appropriate) will, of course, giveyou even more certainty.

To test the circuit, connect thepower supply (in this case, a 9-V bat-tery), and examine the output wave-form on an oscilloscope.

Fig. 8. The second connection made on theboard is marked in the circuit diagram, byrunning a colour marker pen over the rele-vant line in the circuit diagram.


READERS' CORNER65

BOLTON INSTITUTE,ALUMNI ASSOCIATION

May I appeal to any readers who are formerstudents of Bolton Institute of Higher Educationor who, prior to 1982, attended Bolton Collegeof Education (Technical) or Bolton Instituteof Technology. Indeed, we shall be glad tohear from anyone who during the last fiftyyears or so, prior to the Institute's creation,pursued a higher -level course in Bolton, e.g.,at Bolton College of Art or Bolton TechnicalCollege.

Bolton Institute is establishing an AlumniAssociation (an association of former studentsof an educational institution) and we are try-ing to trace anyone who has studied at the in-stitute, no matter when, as we want to reestab-lish contact with them.

We are inviting all former students towrite and let us know what they are doing nowand to join the Bolton Institute AlumniAssociation.

This year we hope the Institute will be-come Bolton's University, and former stu-dents will be invited to celebrate with us.We hope also to establish InternationalAlumni Associations in other countries. Wewill be arranging reunions, giving informa-tion of new developments and sharing newsabout former students through the AlumniMagazine, the first issue of which was pub-lished in January.

Please write to: Jan Lancaster, AlumniRelations Officer, Bolton Institute, Deane Road,Bolton BL3 5AB, or phone (0204) 28851, ex-tension 3808, or fax us on (0204) 399074.

PRODUCT NEWSNEW EPROM EMULATOR FROMSQUARE WAVE ELECTRONICS

Squarewave Electronics has launched theMicroRom, a revolutionary new type ofEPROM Emulator.

The MicroRom is a conventional EPROM

COMPONENT RATINGS

In resistor and capacitor values, decimal pointsand large numbers of zeros are avoided wher-ever possible. Small and large values are usu-ally abbreviated as follows:

P (Pico-) = 10-12n (nano-) = 10-9j_t (micro-) = 10-6m (milli-) = 10-3k (kilo-) = 103M (mega-) = 106G (giga-) = 109

Note that nano -farad (nF) is the internationalway of writing 1000 pF or 0.001 pF.Resistors are1/3 watt, 5% metal film types un-

Emulator miniaturized into a module only11 mm high that plugs directly into yourEPROM socket. Unlike conventional emu-lators, there is no messy ribbon cable. Onceprogramming is complete and the computerconnection removed, the emulator can remainin circuit like a normal EPROM. Because ofits non-volatile storage, the emulator can beused with any computer that has a Centronicsprinter port. No software is needed to run theemulator; just send an ASCII file containingsystems information (such as EPROM size,data format type, any offsets, high or lowreset), followed by the datafile, to the printerport. It can download a 27512 binary file inonly 2 seconds.

Consider the MicroRom as an EPROM withan inbuilt programmer that has an unlimitednumber of write cycles.

For further information, contact SquarewaveElectronics, Unit 25, Imperial House, 64Willoughby Lane, London N17 OSP; tele-phone/fax +44 (0)81 880 9889. See also ad-vert on page 59.

NEW EMULATORS FROMMICROAMPS

Dvelopers working with the 8031/51 mi-crocontroller can get a low-cost, full func-tion, In -Circuit Emulator from MicroAmps.

The ICE51+ features include small size(110x65 mm), operation up to 16 MHz,64 kbytes of battery -backed memory par-tionable in 4 kbyte blocks between programand on -board or off -board data, 64 k hard-ware breakpoints in program and external datamemory, single step and software trace to-gether with a host of other facilities.

The BICEPS51 In -Circuit Emulator iscapable of supporting almost al 8051 deriva-tives using a new technique that combines thebest features of an EPROM emulator with afull -function In -Circuit Emulator.

The BICEPS51 replaces the EPROM inthe circuit on test with 64 kbytes of emula-tion RAM that can be partitioned in 4 kbyte

less otherwise specified.

The direct working voltage of capacitors (otherthan electrolytic or tantalum types) is assumedto be .150 V. As a rule of thumb, a safe valueis about 2x direct supply voltage.

Direct test voltages are measured with a 201d2/Vmeter unless otherwise specified.

Mains (power line) voltages are not listed in thearticles. It is assumed that our readers knowwhat voltage is standard in their part of theworld.

Readers in countries that use 60 Hz supplies,should note that our circuits are usually designedfor 50 Hz. This will not normally cause prob-lems, although if the mains frequency is used

blocks. The device requires a single adaptorto emulate almost all 8051 derivatives. Thepackage comes with high-level debugging,hardware breakpoint capability, cross as-sembler and real-time trace buffer that canbe interrogated 'on the fly' .

For more information contact Micro AMPS66 Smithbrook Kilns, Cranleigh GU6 8JJ; tele-phone +44 (0)483 268 999; Fax +44 (0)483268 397. See also advert on page 41.

SPICEAGE 3 FOR WINDOWS FROMTHOSE ENGINEERS

V3 of SpiceAge for Windows gives an orderof magnitude of speed rise for logic simula-tion over SpiceAge 2, previously believed tobe the fastest analogue simulator of its typeavailable. V3 benchmarks at 9 seconds on thedigital test compared with 120 seconds on V2.Speed gains are also apparent on some ana-logue circuits. To support this, a new 32 -channel logic analyser display is available,more digital models are provided and inputsignal bus structures are supported. TheZetex SPICE library of analogue semicon-ductor models is shipped with V3 and the ana-logue side is further expanded by a brand newopamp model especially developed to ex-ploit the linear extrapolation pragmas pro-vided in SpiceAge's polynomial functions.Not only is this topology more accurate thanmany SPICE models, but is faster to analyse.

For further information, contact ThoseEngineers Ltd, 31 Birkbeck Road, LondonNW7 4BP. Telephone +44 (0)81 906 0155;fax +44 (0)81 906 0969. See also advert onpage 58.

IMPULSE RESPONSEMEASUREMENT AND PROCESSINGThe dedicated IMP board from Falcon Acous-tics, which is similar in operation to the KEFand Bowers & Wilkins impulse measure-ment, generates an impulse which is sent tothe loudspeaker via an amplifier (your hi-fi

for synchronization, some modification maybe required.

The international letter symbol U' is used forvoltage instead of the ambiguous . The let-ter V is reserved for 'volts'.

The size of a metric bolt or screw is definedby the letter M followed by a number corre-sponding to the overall diameter of the threadin mm, the x sign and the length of the bolt orscrew, also in mm. For instance, an M4x6 bolthas a thread diameter of 4 mm and a length of6 mm. The overall diameter of the thread in theBA sizes is: 0 BA= 6.12 mm; 2 BA =4.78 mm;4 BA = 3.68 mm; 6 BA = 2.85 mm; 8 BA =2.25 mm.


66

amplifier?). The output pulse is picked up bya microphone and fed back into the IMPwhere it is digitized and then fed into anIBM (compatible) computer via the printerport. The IMP software then analyses theinput via Fourier transforms and outputs theresults on to the computer screen in graph-ical form in the shape of amplitude and phaseresponse curves. Full control is via the PC.The amplifier output can be sampled via aprobe to correct for errors in the pulse spec-trum and amplifier response.

IM P allows the collection and analysisof 12 -bit analogue data up to 4,095 samplesin length and sample rates are selectable ateither 61.441 kHz or 1.92 kHz which, alongwith the internal filtering, allows measure-ments from several hertz to 20 kHz.

Further information from Falcon AcousticsLtd, Tabor House, Norwich Road, Mulbarton,Norfolk NR14 8JT, England. Telephone+44 (0)508 78272; fax +44 (0)508 70986.

CORRECTIONSDIGITAL DIAL (January 1994)

An attentive reader has drawn our attentionto the fact that the digital dial can not beused in conjunction with the receiver illus-trated (a Yaesu Type FRG -7) since the IF ofthat receiver is much too high for the dial.Sorry for that oversight! [Editor]

VHF/UHF TUNER (Oct/Nov 1993)The tuner module used in this design is nolonger in production with Philips and itsavailability will thus become a problem.Fortunately, the Type UV916H is an excel-lent alternative. The snag is, however, thatthis unit is slightly smaller than the UV816,

so that the antenna connector no longer pro-trudes from the enclosure. This can be over-come by terminating the antenna cable intoa coaxial plug and making the entrance holeslightly larger. Moreover, one of the twoearth tags of the UV916H must be connectedat a different position.

LETTERSSCART SWITCHING BOX

(December 1993)I have a few problems with this project,which I believe have to do with the connec-tions. Pin 1 of one connector is linked topin 2 of the other. The same is true of pins 3and 19, which are linked to pins 6 and 20 re-spectively. All other pins are interlinked asone would expect, i.e., pin 5 to pin 5, pin 10to pin 10, and so on.L. Bastiaenssen

Ina SCART cable, the wiresfor the video andaudio connections are always crossed. Thatis why the video output (pin 19) at one endof the cable is linked to the video input(pin 20) at the other end. This arrangementensures that the input of one piece of equip-ment is always connected properly to theoutput of another. There is, therefore, noth-ing wrong with your cable.

Note that two pieces of equipment mustnever be connected simultaneously to K3and K5/K6. Use SCART connector K3 or thephono plugs K5/K6, but not both at the sametime! [Editor]

PRECISION CLOCK FOR PCs(November 1993)

I have encountered a problem with the Precision

clock for PCs. I have an IBM (compatible)PC486 and have, as stated in the article,complemented the CONFIG.SYS file withthe following (last) line:DEVICE C:\MSDOS\DCFCLOCK.SYS.

I should be pleased if you would tell me:1. Whereto should the files of the softwareprovided (DCFCLOCK.ASM, DCF-CLOCK.DOC and DCFCLOCK.SYS becopied? To the root, the MSDOS or a sepa-rate directory?2. Once the files have been loaded, how isthe program called up to initialize the driverand to fill the options P, I, S, B and D?(M. Meersschaut)

The file DCFCLOC .ASM is the assembler list-ing of the program, which you no longerneed (it is of interest only to dyed-in-the-wool programmers). The file DCF-CLOCK.DOC contains the instructions forthe program, which you can read with a wordprocessing program. It is not necessary tostore this file on a hard diksk.

The only program that you need to copyto the hard disk is DCFCLOCK.SYS. Placethis file in the directory containing the DOScommands (e.g., C ADOS). Add aline that in-dicates where the computer can find thatprogram to CONFIG.SYS (in C:\), e.g. DE-VICE = C:\DOS\DCFCLOCK.SYS. Other suf-fixes may be added for changing certain set-tings (see DOC file), but even without thesethe system should work correctly.

Note, however, that the receiver circuit mustbe connected to the COM port 2 and that thecomputer must be restarted after the softwarehas been installed. The program will then au-tomatically set the correct time in the inter-nal clock of the PC every minute.

[Editor]

Produced and published by ELEKTOR Unit 4, Gibbs Reed Parm GERMANY NETHERLANDSELECTRONICS (Publishing) Pashley Road Elektor Verlag GmbH Elektuur BV

TICEHURST TN5 7HE Susterfeld Stral3e 25 Peter Treckpoelatreat 2-4Editor/publisher Len Seymour Telephone (0580) 200 657 (National ) 5100 AACHEN 6191 VK BEEKTechnical Editor J Bulling or +44 580 200 657 (International) Editor E J.A. Krempelsauer Editor. PE L, Kersemakers

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Les Trots Tine uls TEL AVIV 61410 Editor Bill CedrumSubscriptions: B P 59; 59850 NIEPPE Publisher M AvrahamWorld Wide Subscription Service Ltd Editor G.0 P. Raedersdorf


67

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!HELP! Can anyone suggest a source o0 kV 20 mA fast diodes for my home-brew

switch -mode PSU? Phone Alan on 081 800 0982.

WANTED. 27128 EPROMs 21 V. Please phone(0222) 566 413.

WANTED. Information on PCB and schematicprograms used in Elektor Electronics. Pleasewrite to William Wallace, 934 Sharon Drive,Lebanon, Ohio 45036, USA., or phone (513)932-1277.

Increase your electronicsknow-how and skills

The speed and intensity with which electronics penetrates our daily livesat home, at work, or in our car, tends to make us forget that we can useelectronics creatively by building designs with a practical applicationand having the satisfaction of a successfully finished project. ElektorElectronics, which is distributed all over the world, can help you achievethese goals. Throughout the year, the magazine features originalconstruction projects, informative articles and news on the gamut ofelectronics, science & technology, book reviews and information on newproducts. The past 11 issues contained 80 major and 97 minorconstruction articles, 21 articles of an educative or instructional nature,and 10 articles dealing with Science & Technology.If you wish to increase your electronics know-how and skills, take out anannual subscription to Elektor Electronics by writing or faxing to

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You will then have the convenience of having the magazine delivered toyour home, and the peace of mind that you will not miss any issue. The1994 worldwide rates for an annual subscription (11 issues) are shownon page 72.

WANTED. Acorn Atom with disk drive, anycondition. Please ring (0729) 860 224.

WANTED. Epsom FX800 circuit. Please writeto R. Click, 12 Avon Grove, Cheadle, Stoke onTrent, Staffs ST10 1QR.

FOR SALE. Philips scope PM3217, 50 MHz,calibrated will October 1994, with leads andpouch. £250 o.n.o. Please ring 091 372 0923.

HELP! I need some information about theOrcad program. I need the file `LIB EDIT' for3.21 version. Thanks in anticipation. Please writeto Luis M. Pinto, C. de Vila-Nespereira, 4620Lousada, Portugal.

FOR SALE. PDP 11/23 main frame, 3 RLO2disk, 2 VT320 terms, 12 hard drive disks, work-ing. £250 o.n.o. Please phone (0642) 711 368.

WANTED. Information/manual W.H.Y. for S.E.Labs 2001A frequency response analyser.Please ring (0602) 372 109.

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68

Project

PRODUCT OVERVIEMARM 11396

ELEKTOREL ECTRUNIC-S

A number of projects carried in Elektor Electronics are supported by ready-made printed -circuit boards (PCBs), self-adhesive front panel foils, ROMs, EPROMs, PALs, GALs,microcontrollers and diskettes, which may he ordered through our Readers Services using theorder form printed every month opposite the Readers Services page.The list printed here is complementary to the shorter one opposite the Readers Services pageelsewhere in this issue. This two -page overview of all currently available products is regularlyupdated and appears in the March, June, September and December issues of ElektorElectronics.Items marked with a dot (*) following the product number are in limited supply only, and theiravailability can not be guaranteed by the time your order is received.Items not listed here or on this month's Readers Services page are not available.The artwork for making PCBs which are not available ready-made through the ReadersServices may be found in the relevant article (from March 1990 onwards).Prices and item descriptions subject to change. Prices can be confirmed on request at the timeof ordering.

Project No. Price Project(E) (USS)

PRINTED -CIRCUIT BOARDS

1987JANUARY 1987Top -of -the -rangepreamplifier 86111-2 26.45 52.90

MARCH 1987MSX EPROMmer 87002 11.15 22.30

MAY 1987MIDI signal distribution 87012

OCTOBER 1987Low -noise microphonepreamplifier 87058

870 17.40

4.05 8.10

NOVEMBER 1987BASIC computer 87192 23.80 47.60

1988JANUARY 1988Stereo limiter 87168 8.50 17.00

MARCH 1988Computer -controlledslide faderLow -noise preamplifierfor FM receiversSignal divider forsatellite TV receivers

APRIL 1988Fuzz unit for guitars

MAY 1988Plotter

87259

880041

880067

ST and ArchimedesMIDI control unit

Low -budget capaci-tance meter

No. Price(E) (US$)

880109 8.65 17.30880178-1 10.65 21.30880178-2 7.80 15.60

UPBS-1 2.30 4.60

FEBRUARY 1989Digital Model Train 87291-1 4.95 9.90VHF receiver 886127 8.75 17.50

MARCH 1989Power line modemCentronics buffer

APRIL 1989Digital Model TrainFunction generatorTriplet

880189 7.15 14.30890007-1 23.05 46.10890007-2 2.55 5.10890007-3 9.80 19.60

87291-2/3 5.05 10.10UPBS-1 2.30 4.60

890013-1 7.80 15.60890013-2 8.00 16.00

Multi -point IR control 890019-1 4.05 8.10890019-2 4.75 9.50

Video recording amplifier ELV project

MAY 1989RDS decoder 680209 5.30 10.60Digital Model Train (4) 87291-4 6.15 12.30DTMF system decoder 890060 7.65 15.30Sine -wave converter UPBS-1 2.30 4.60S-VHS-to-RGB converter ELV project

18.80 37.60JUNE 1989

7.65 15.30 Echo unit ELV project

5.90 11.80 JULY/AUGUST 1989MIDI keyboard interfacedecoder board 890105-1 8.25 16.50

87255 7.65 15.30 controller boardTracking tester ELV projectFloppy disk monitor 890078 5.00 10.00

87167 13.50 27.00 Function generator UPBS-1 2.30 4.60

JUNE 1988Wideband active aerial 880043-1 for SW receivers 880043-2

JULY/AUGUST 1988Frequency read-out forSW receivers

OCTOBER 1988Preamplifier forpuristsPeripheral modulesfor BASIC computer

7.05 14.105.60 11.20

SEPTEMBER 1989Digital Model TrainResonance meter

87291-6 7.85 15.70886071 4.60 9.20

OCTOBER 1989CD error detector 890131

880039 21.60 43.20 RGB-to-CVBS converter

880132-1 880132-2.

880159

NOVEMBER 1988Bus interface for hi-resLCD screens 880074 LFA-150 -a fast 880092-1 power amplifier 880092-2 Harmonic enhancer 880167

DECEMBER 1988LFA-150 -a fastpower amplifierCVBS-to-TTL adaptorAutonomous I/Ocontroller

1989

880092-3e880092-4e

880098

880184

NOVEMBER 19896.95 13.90 Digital Model Train (8) 87291-5

14.40 28.80

5.90 11.80

19.709.959.207.40

7.507.605.70

39.4019.9018.4014.80

15.0015.2011.40

18.00 36.00

JANUARY 1989Fax interface for Atari

DECEMBER 1989Digital Model TrainEPROM simulatorHard disk monitorIC testerLF/HF signal tracerSolid-state preamp

1990

87291-7890166890186

890183890170-1'890170-3'

7.05 14.10ELV project

51.10 102.20

10.30 20.6011.75 23.5012.95 25.90

ELV project9.40 18.80

13.80 27.6010.60 2120

JANUARY 1990Video mixer (1)Mini EPROMprogrammerAll solid-statepreamplifierSimple AC milli -voltmeter

87304-1

890164

890170-2'

32.00 64.00

8.25 16.50

18.50 37.00

900004 7.65 15.30

*The four PCBs required for the preamplifier (2 x

Project No. Price(E) (USS)

890170-1; 1x 890170-2 and 1x 890170-3) areavailable as a package, ref. 890170-9, at adiscounted price of £48.15 (USS96.30).

FEBRUARY 1990Initialisation aid for 900007 16.75printersDigital Model Train (11) 87291-8 5.30Reflex MW AM receiver UPBS-1 2.30Video mixer (2) 87304-2 19.10Capacitance meter 900012 8.50

33.50

10.604.60

38.2017.00

MARCH 1990Audio/video modulator ELV projectDigital model train (12) 87291-9 4.10 8.20Power line monitor 900025 5.60 11.20Video mixer (3) 87304-3 41.70 83.40

APRIL 1990Digital model train (13) 87291-10 4.70 9.40Q meter 900031 7.05 14.10RS -232 splitter 900017-1 8.50 17.00

900017-2 5.30 10.60Wiring allocation tester ELV project

MAY 1990Acoustic temperaturemonitor UPBS-1 2.30 4.60Budget sweep/functiongenerator 900040 8.25 16.50Centronics ADC/DAC 900037D 17.90 35.80PC servicing card ELV projectTransistor characteristicplotting 900058 5.60 11.20

JUNE 1990Electronic load simulator 900042 14.10 28.20MIDI master keyboard Doepfer ElektronikMini EPROM viewer 900030 21.15 42.30Power zener diode UPBS-1 2.30 4.60Remotely controlledstroboscope ELV project

JULY/AUGUST 1990Battery tester ELV projectCompact 10A powersupply 900045 13.50 27.00Intermediate projects UPBS-1 2.30 4.60Mini FM transmitter' 896118 5.00 10.00Sound demodulator forsatellite -TV receivers 900057 4.40 8.80Audio power indicator 904004 4.40 8.80Four -monitor driverfor PCs 904067 6.15 12.30

can not be supplied to readers in the UK

SEPTEMBER 1990High -current hEE tester 900078 6.45 12.90Infra -red remotecontrol 904085/86 7.95 15.90Sound generator ELV project

OCTOBER 19906P -controlled telephoneexchangeS-VHS/CVBS-to-RGBconverter

900081 21.15 42.30

900055. 14.40 28.80

NOVEMBER 1990400 -watt laboratory PSU 900082 12.95 25.90Dubbing mixer EV7000 ELV projectMedium -power audio 900098 10.60 21.20amplifierProgrammer for the 8751 900100 8.25 16.50PT100 thermometer 900106 5.90 11.80

No Price(E) (USS)

DECEMBER 1990Active mini subwoofer 900122-2 6.15 12.30Milliohmmeter 910004 5.90 11.80Phase check foraudio systems 900114-1/2 9.40 18.80PC -controlled Video-text decoder (1) ELV projectSignal suppressor forall -solid state preamp 904024 4.40 8.80

1991JANUARY 1991Logic analyser (1):- BusboardPC controlled Video-text decoder (2)SWR meter

900094-4 10.60 21.20

ELV project900013 3.55 7.10

FEBRUARY 1991Logic analyser (2):- RAM board 900094-2 18.50 37.00- Probe board 900094-3 5.00 10.00Multifunction measure-ment card for PCs 900124-1 28.20 56.40MIDI -to -CV interface Doepfer ElektronikRDS decoder:- demodulator board 880209 5.30 10.60- processor board 900060 7.65 15.30

MARCH 1991The complete preamplifier:- input board 890169-1 26.10 52.20- main board 890169-2 39.35 78.70Electronic exposuretimer 900041 10.85 21.70PC -controlled weatherstation (1) 900124-3 4.40 8.802-m band converter 900006-1 5.00 10.00

APRIL 1991Logic analyser (3):- control board 900094-5 18.50 37.00MIDI programmechanger 900138 6.75 13.508 -bit I/O for Atari 910005 12.35 24.706-m band transverter 910010 11.45 22.90Wattmeter:- meter board 910011-1 6.45 12.90- display board 910011-2 4.10 8.20Moving -coil (MC)preamplifier 910016 10.60 21.20Dimmer for halogen lights:- transmitter 910032-1 4.10 8.20- receiver 910032-2 4.40 8.80PC -controlled semi-conductor tester ELV project

MAY 199180C32/8052 Computer 910042 12.05 24.10Battery tester 906056 4,10 8.20Laser (1) ELV projectMoving -magnet (MM)preamplifier 900111 6.75 13.50Universal I/O interfacefor IBM PCs 910046 10.85 21.70

JUNE 1991Universal battery charger 900134 9.40 18.80Logic analyser - 4- power supply board 900094-7 8.80 17.60- Atari interface 900094-6 12.65 25.30- IBM interface 900094-1 14.40 28.80Digital phase meter(set of 3 PCBs) 910045-1/2/3 26.15 52.30Light transceiver UPBS-1 2.30 4.60Variable AC PSU 900104 6.15 12.30Light switch w. TV IR ric 910048 5.60 11.20RTC for Atari ST 910006 6.15 12.30

JULY/AUGUST 1991Multifunction I/O for PCs 910029 24.40 48.80B/W video digitizer 910053 22.60 45.20Stepper motor board - 2:- power driver board 910054-2 28.50 57.00Laser - 3 ELV projectLED voltmeter 914005 5.60 11.20Wien bridge 914007 4.10 8.20Angled bus extensioncard for PCs 914030 12.05 24.10Sync separator 914077 4.40 8.80

SEPTEMBER 1991Peak indicator for loud-speakers ELV projectTimecode interface for slide control:- main board 910055 24.40- display board 87291-9a 4.10Asymm-symm converter 910072 5.60

48.808.20

11.20

OCTOBER 1991PC -controlled weatherstation (2) 900124-2 3.80 7.60Digital function generator- main board 910077-1 21.75 43.50- display board 910077-2 12.65 25.30Audio spectrum shiftencoder/decoder 910105 10.35 20.70

NOVEMBER 1991Relay card for uni-versal I/O interface 910038 12.95 25.90Dissipation limiter 910071 4.40 8.80Digital function generator


Printed circuit boards whose number is followed by a sign are only available in combination with theassociated software item, and can not be supplied separately. The indicated price includes the software.

Project

69

ROMS - EPROMS - PALS - GALS - MICROCONTROLLERSNo. Price Project(£) (US$)

- sine converter 910077-3- R/T converter 910077-4Class -A power amplifier (1):

880092-1880092-2

Timer for CH systems UPBS-2

DECEMBER 1991Class -A power amplifier (2):

880092-3880092-4

Economy power supply 910111 al. programmable filters 910125Amiga mouse/joystickswitch 914078Safe solid-state relay 914008 Slave mains on/offcontrol Mark -2 914072 Wideband antennaamplifier

1992

15.00 30.0012.35 24.70

9.95 19.909.05 18.103.80 7.60

ELV project

No. Price(£) (US$)

Printer sharing unit 920011Sound sampler for Amiga 920074Difference thermometer 920078Low -power TTL-to-RS232 interface

14.706.755.30

29.4013.5010.60

920127 3.55 7.10

ECEMBER 1992Digital audio/visual system(incl. EPROM 6171) 920022+ 34.10

7.50 15.00 1.2 GHz multifunction7.60 15.20 frequency meter9.40 18.80 (incl. EPROM 6141) 920095+ 29.40 58.806.75 13.50 Output amplifier for ribbon

loudspeakers 920135-1 19.40 38.804.10 8.20 920135-2 7.95 15.903.80 7.60 Peak -delta NiCd charger 920147 6.10 8.20

IDC-to-boX header adaptor924049 6.45 12.906.45 12.90 Mini keyboard for Z80 924047 12.35 24.70

800552 pP system 924071 20.00 40.00Mains power -on delay 924055 6.45 12.90

JANUARY 1992CD player 910146Fast precise thermometer 910081Low -frequency counter- input board 910149-1- display board 910149-2Mini Z80 system 910060Prototyping board forIBM PCs 910049PC -controlled weather 900124-5station (3)

FEBRUARY 1992Audio/video switchingunit 91013012C interface for PCS 910131-1Measurement amplifier 910144Mini square wavegenerator 910151RAM extension for miniZ80 system 910073Switch -mode powersupply 920001

MARCH 19928751 emulatorA-D/D-A and I/O forI2C busAF drive indicatorCentronics line boosterFM tuner (tuner board)LC meterMIDI optical link

920019

910131-2920016910133920005920012920014

APRIL 199280C32 SBC extension 9101092 -metre FM receiver 910134Comb generator 920003AD232 converter 920010Automatic NiCd charger UPBS-1LCD for L -C meter 920018Milli -ohm meter adaptor 920020

May 19921.3-GHz prescaler 914059Compact mains supply 920021FM tuner - 3 (PSU) 920005-2GAL programmer 920030NICAM decoder 920035

JUNE 19924 -Megabyte printer buffer 910110Audio -video processor - 2I2C display 920004FM tuner - 4:- mode control board 920005-3- synthesizer board 920005-5Guitar tuner 920033Multi -purpose Z80 card 920002

JULY 199212VDC to 240VAC inverter- main board 920039-1- power board 920039-2Audio DAC - 1 920063-1Optocard for universalPC I/O bus 910040 12.95 25.90Audio -video processor - 3 ELV projectFM tuner - 5:- keyboard/display 920005-4 14.40 28.80- S -meter 920005-6 3.80 7.60RS232 quick tester 920037 5.00 10.00Small projects:Water pump control forsolar power system 924007 7.35 14.70Simple power supply 924024 5.00 10.00Wideband active teles-copic antenna 924102 3.25 6.50

1993JANUARY 1993PAL test pattern generator(incl. GAL 6211) 920129+ 15.30 30.60Multi -core cable tester- matrix board 926079 17.05 34.10- slave unit 926084 6.20 12.40- master unit 926085 8.25 16.50

FEBRUARY 1993U2400B NiCd batterycharger 920098 8.75 17.50Digital -audio enhancer 920169 14.25 28.5012C opto/relay card 930004 11.00 22.00Watt-hour meter (PCBs -1and -2, and EPROM 6241)920148+ 37.25 74.50

MARCH 1993Linear sound pressuremeterElectrically isolatedRS232 interface

930006 7.00 14.00

920138 10.25 20.50

APRIL 1993Audio power meter 930018 10.25 20.50Video digitizer for PCs

12.05 24.10 (incl. disk 1831) 930007+ 37.00 74.00Infrared receiver for 80C32

6.15 12.30 single -board computer5.60 11.20 (incl. disk 1791) 920149+ 14.50 29.005.90 11.80 4MB printer buffer card 920009 27.50 55.00

21.15 42.308.80 17.606.15 12.30

8.25 16.508.50 17.00

5.00 10.006.45 12.90

10.60 21.20

21.15 42.3010.00 20.00

11.75 23.5014.40 28.8013.50 27.00

5.30 10.60

2.35 4.70

4.40 8.80

13.5010.30

8.5012.35

2.304.704.40

5.007.358.80

11.1515.00

27.0020.6017.0024.704.609.408.80

10.0014.7017.6022.3030.00


4.70 9.40

5.60 11.2010.85 21.7010.00 20.0020.25 40.50

SEPTEMBER 1992EPROM emulator - II 910082Audio/video processor - 4Audio DAC - 2 920063-2

11.15 22.306.45 12.908.50 17.00


18.80 37.60

OCTOBER 1992Audio DAC - 3 920063-3 26.45Mains sequencer 920013 17.35Wideband active antenna 924101 3.25RDS demodulator 880209 5.30

52.9034.70

6.5010.60

MAY 1993FM stereo signal generator920155VHF/UHF receiver 926001Philips preamplifier 930003Workbench PSU 930033

920075-1

23.0019.00

7.5021.50

4.70

68.20

46.0038.0015.0043.00

9.40

JUNE 1993Spectrum VU meter 920151 13.00 26.00GAL programmer upgrade930060 4.50 9.00Digital frequency readoutfor VHF/UHF receiver 926001-2 11.50 23.00Inexpensive phase meter- main board 930046 9.00 18.00- meter board 920018 4.75 9.50

JULY/AUGUST 1993Active 3 -way loudspeakersystem 930016 21.50 43.00Maxi micro clock 930020 15.50 31.00Four -fold DAC for PCs 930040 Koller ElectronicSMD soldering station 930065 9.50 19.00VHF -low converter 926087 15.50 31.00I2C bus fuse 15 on I PCB) 934016 8.00 16.00Voice operated recording 934039 6.00 12.00General transformer PCB 934004 6.50 13.00Plant humidity monitor 934031 4.50 9.00Plant humidity monitor(supply) 934032 4.00 8.00

SEPTEMBER 1993Fuzzy logic multimeter -1920049-2 20.00 40.00Linear temperaturegauge 920150 7.05 14.10PC -aided transistortester 920144 9.75 19.50Harmonic enhancer 930025 13.50 27.00ITC alphanumericaldisplay (incl. disk 1851) 930044+ 14.25 28.50Mini micro clock 930055 7.50 15.00950-1750 MHz converter UPBS-1 1.95 3.90

OCTOBER 1993Stereo mixer UPBS-1 1.95 3.90MIDI channel monitor 930059 14.00 28.00Ah meter with digitaldisplay 930068 14.00 28.00Autoranging frequencyreadout 930034 12.50 25.00ROM -gate switchover forAtari ST 930005 30.25 60.50Microntroller-driven NiCdbattery charger (incl.programmed ST62E15) 920162+ 25.50 51.00Fuzzy logic multimeter - 2(incl. disk 1721) 920049-1+ 23.75 47.50

r-oi November 1993 to March 1994 foams seepage 70 of this issue

Article/Project' Issue Order Description Pricecode (£) (US$)

Multifunction measurement card for PCs 2/91 561 1 x 16L8 10.30 20.60The digital model train series 572 1 x 2764 11.75 23.50Darkroom clock 2/90 583 1 x 27128 10.85 21.70Video mixer 3/90 5861 1 x 2764 11.75 23.50Four -sensor sunshine recorder 6/90 5921 1 x 27128 11.75 23.50µP -controlled telephone exchange 10/90 5941 1 x 27128 15.30 30.60RDS decoder 2/91 5951 1 x 2764 15.30 30.60MIDI programme changer 4/91 5961 1 x 2764 15.30 30.60Logic analyser (series) see under Cr ISKETTES below

Logic analyser (IBM interface) 6/91 5971 1 x PAL 16L8 8.25 16.50MIDI -to -CV interface 2/91 5981 1 x 2764 15.30 30.60Multifunction I/O card for PCs 7-8/91 5991 1 x PAL 16L8 8.25 16.50Amiga mouse/joystick switch 12/91 6001 1 x GAL 16V8 8.25 16.50Stepper motor board 6/91 6011 1 x PAL 16L8 8.25 16.504-MByte printer buffer (6/92 and 4/93) 6041 1 x 27C64 15.30 30.608751 emulator (incl. system disk 5.25 in.) 3/92 6051 1 x 27C64 29.40 58.80EMON51 (incl. course disk 1661) (series) 6061 1 x 27256 20.00 40.00Connect 4 12/91 6081 1 x 2764 15.30 30.60EMON51 (incl. course disk 1681) (series) 6091 1 x 27256 20.00 40.00FM tuner 7/92 6101 1 x 27C256 15.30 30.60Multi -purpose 280 card: GAL set 6/92 6111 2 x GAL 16V8 11.15 22.30Multi -purpose Z80 card: BIOS 6/92 6121 1 x 27128 15.30 30.60TV test pattern generator (80C32 SBC) 3/93 6151 1 x 27256 15.30 30.601.2 GHz multifunction frequency meter 12/92 6141 1 x 27C256 11.45 22.90Digital audio/visual system 12/92 6171 1 < 27C256 10.30 20.60Digital audio/visual system (software package) 2/93 6181 EPROM. GAL. and disk 30.50 61.00PAL test pattern generator 1/93 6211 1 x GAL 20V8 9.40 18.80Watt-hour meter 2/93 6241 1 x 27256 10.00 20.00Four fold DAC 7-8/93 6251 1 x GAL 10.75 21.50Multipurpose display decoder 7-8/93 6261 1 x 2764 11.50 23.00Digital hygrometer 11/93 6301 1 x 2764 14.50 29.008751 programmer 11/90 7061 1 x 8751 46.40 92.80Microcontroller NiCd charger 10/93 7071 1 x ST62E15 10.00 20.00Maxi micro clock (clock) 7-8/93 7081 1 x ST62T10 11.50 23.00Maxi micro clock (darkroom timer) 7-8/93 7091 1 x ST62T10 11.50 23.00Maxi micro clock (cooking timer) 7-8/93 7101 1 x ST62T10 11.50 23.00Mini micro clock (clock) 9/93 7111 1 x ST62T15 11.50 23.00Mini micro clock (darkroom timer) 9/93 7121 1 x ST621-15 11.50 23.00Mini micro clock (cooking timer) 9/93 7131 1 x ST62715 11.50 23.00VHF/UHF TV tuner 11/93 7141 1 x 87C51 25.75 51.50* For pre -1990 project EPROM5 see the December 1992 Product Overview or contact our Dorchester office

DISKETTESArticle/Project` Issue

EPROM emulator II 9/92Multifunction measurement card (MMC) for PCs 2/91Logic analyser: IBM software & GAL ICLogic analyser: Atari software & GAL ICPlotter driver (D. Sijtsma)8 -bit I/O interface for Atari STTektronix/Intel file converterB/W video digitizer for ArchimedesTimecode interface for slide controllerReal-time clock for Atari ST24 -bit colour extension for video digitizerPC -controlled weather station (3)(supersedes 1551 and 1561)8051/8032 assembler course (IBM version)A-D/D-A and I/O for I2C bus8051/8032 assembler course (Atari version)AD232 converterGAL programmer (upgrade: June 1993)Multi -purpose Z80 cardFuzzy Control OnePascal routines for MMC for PCsSpeech/sound memoryPC -aided transistor testerInt ra-red receiver and DTMF decoder for80032 single -board computerI2C opto/relay cardVideo digitizer for PC5GAL programmer for Amiga 6/93ITC alphanumerical display 9/93Philips preamplifier 5/93GAL programmer (excl. Opal Jr. disks)X2404 -to -8751 interfacing

7-8/917-8/919/914/914/917-8/919/916/9111/911/92

(series)3/92series

Order Disk sizecode

12914611491150115411571158115911611162116311641

5.25 -inch5.25 -inch5.25 -inch3.5 -inch5.25 -inch3.5 -inch5.25 -inch3.5 -inch5.25 -inch3.5 -inch3.5 -inch5.25 -inch

Price(0) (US$)

6.757.65

19.4019.4011.15

7.657.65

11.157.657.65

11.157.65

13.5015.3038.8038.8022.3015.3015.3022.3015.3015.3022.3015.30

1661 5.25 -inch 7.65 15.301671 order as 1821 (see below)1681 3.5 -inch 7.65 15.30

4/92 16915/92 8 6/93 17016/92 171110/93 172110/92 175112/92 17719/93 1781

5.25 -inch5.25 -inch (3 x)5.25 -inch5.25 -inch5.25 inch5.25 inch3.5 inch

3 & 4/93 1791 5.35 -inch2/93 1821 5.25 inch4/93 1831 5.25 inch

1841 3.5 inch1851 5.25 inch1861 5.25 inch

6/93 1881 5.25 inch6/93 1891 5.25 inch

7.65 15.3011.15 22.30

7.65 15.307.75 15.509.70 19.407.65 15.307.50 15.00

7.507.65

14.5011.00

8.508.50

10.758.50

15.0015.3029.0022.0017.0017.0021.5017.00

For pre -1991 project diskettes see the December 1992 Product Overview or contact our Dorchester office

SELF-ADHESIVE FRONT PANEL FOILSArticle/Project*

WattmeterUniversal NiCd battery chargerLogic analyserDigital phase meterVariable AC power supplyTimecode interface for slide controllerDigital function generator4 -Megabyte printer bufferEconomy power supplyMeasurement amplifierCD playerFM tuner4 -Megabyte printer buffer insertion cardLC meterDigital audio/visual system

Guitar tunerNICAM decoder12VDC-to-240VAC inverterAudio DAC1.2GHz multifunction frequency meterU2400B NiCd battery chargerWorkbench PSUInexpensive phase meter

Issue Order code

4/91 910011-F6/91 900134-F(series) 900094-F6/91 910045-F6/91 900104-F9/91 910055-F10/91 910077-F6/92 910110-F12/91 910111-F2/92 910144-F1/92 910146-F(series) 920005-F3/93 920009-F3/92 920012-F(series) 920022-F1

920022-F2920022-F3

6/92 920033-F5/92 920035-F7/92 920038-F10/92 920063-F12/92 920095-F2/93 920098-F4/93 930033-F6/93 930046-F

Price(0) (US$)

9.706.45

10.3011.7516.45

8.8010.6011.4510.608.80

12.0513.20

8.2511.4510.0019.4028.80

8.808.25

16.1510.0013.808.75

17.0017.25

19.4012.9020.6023.5032.9017.6021.2022.9021.2017.6024.1026.4016.5022.9020.0038.8057.6017.6016.5032.3020.0027.6017.5034.0034.50

NOVEMBER 1992


" For 1990 project front panel foils see the September 1993 Product Overview or contact our Dorchester office

70

READERS SERVICESExcept in the USA and Canada, all orders, except forsubscriptions and past issues (for which see below),must be sent BY POST to our Dorchester office usingthe appropriate form opposite. Please note that wecan not deal with PERSONAL CALLERS, as no stockis carried at the editorial and administrative office.Readers in the USA and Canada should send orders,except for subscriptions (for which see below), to OldColony Sound Lab, Peterborough, whose full addressis given on the order form opposite. Please includeshipping cost according to total order value. For sur-face delivery in the USA, if order is less than $50, in-clude $3; $50+, $4. For Canada surface, if less thanUS$50, include US$5; US$50+, US$7.50. For air orother deliveries, please inquire. Please allow 4-6weeks for delivery.All other customers must add postage and packingcharges for orders up to £25.00 as follows: UK andEire £1.95; surface mail outside UK £2.45; Europe(airmail) £2.95; outside Europe (airmail) £3.70. For or-ders over £25.00, but not exceeding £100.00, thesep&p charges should be doubled. For orders over£100.00 in value, p&p charges will be advised.

SUBSCRIPTIONS & PAST ISSUESSubscriptions and past issues, if available, should beordered from Worldwide Subscription Service Ltd,Unit 4, Gibbs Reed Farm, Pashley Road, TICE-HURST TN5 7HE, England. For subscriptions, usethe order form on the opposite page. Prices of past is-sues (except July/August and December), includingpostage for single copies, are £2.70 (UK and Eire);£3.00 (surface mail outside UK); £3.20 (air mailEurope); £3.95 (airmail outside Europe). Prices of pastJuly/August and December issues, including postagefor single copies, are £3.75 (UK); £4.00 (surface mailoutside UK); £4.25 (airmail Europe); and £5.00 (air-mail outside Europe).

PAST ARTICLESPhotocopies of articles from January 1978 onwardscan be provided, postage paid, at £1.95 (UK and Eire),£2.10 (surface mail outside UK), £2.45 (airmailEurope), or £2.70 (airmail outside Europe). In case anarticle is split into instalments, these prices are applic-able per instalment. Photocopies may be orderedfrom our editorial and administrative offices.

COMPONENTSComponents for projects appearing in Elektor Elec-tronics are usually available from appropriate advertis-ers in this magazine. If difficulties in the supply ofcomponents are envisaged, a source will normally beadvised in the article. It should be noted that thesource(s) given is (are) not exclusive - other suppli-ers may also be able to help.

BOOKS

For book availability, see advertisement on page 58.

SHELF BOXElektor Electronics shelf box £2.95 $6.00

FRONT PANELS

PROJECT

Timecode interfaceDigital functiongenerator

4 -Megabyte printerbufferFM tuner4MB printer buffer cardLC meterGuitar tunerNICAM decoder12VDC to 240VACinverter

Audio DACDig. audio/visual system

1.2 GHz multifunctionfrequency meterU2400B NiCd batterycharger

No.

910055-F

910077-F

910110-F920005-F920009-F920012-F920033-F920035-F

920038-F920063-F

920022-F1920022-F2920022-F3

920095-F

920098-F

Price Price(£) (US$)

8.80 17.60

10.60 21.20

11.45 22.9013.20 26.408.25 16.50

11.45 22.908.80 17.608.25 16.50

16.15 32.3010.00 20.0010.00 20.0019.40 38.8028.80 57.60

13.80 27.60

8.75 17.50

PROJECT No.

Workbench PSU 930033-FInexpensive phase meter 930046-FMini preamplifier 930106-FAF rms voltmeter 930108-F

Price Price(£) (US$)

17.00 34.0017.25 34.50Not available17.25 34.50

EPROMS / PALS / MICROCONTROLLERS

Amiga mouse/joystickswitch (1 x GAL 16V8) 6001 8.25 16.504 -Megabyte printer buffer(1 x 2764) 6041 15.30 30.608751 emulatorincl. system disk (MSDOS) 6051 29.40 58.80Connect 4 (1 x 27C64) 6081 15.30 30.60EMON51 (8051 assemblercourse) (1 x 27256 +disk 1661) 6061 20.00 40.00EMON51 (8051 assemblercourse) (1 x 27256 +disk 1681) 6091 20.00 40.00FM tuner (1 x 27C256) 6101 15.30 30.60Multi -purpose Z80 card:GAL set (2 x GAL 16V8) 6111 11.15 22.30Multi -purpose Z80 card:BIOS (1 x EPROM 27128) 6121 15.30 30.601.2 GHz multifunctionfrequency meter(1 x 27C256) 6141 11.45 22.90Digital audio/visual system(1 x 27C256) 6171 10.30 20.60TV test pattern generator(1 x 27256) 6151 13.00 26.00DiAV system. Package:1 x 27512; 2 x GAL; 1 xfloppy disk (MSDOS) 6181 30.50 61.00PAL test pattern generator(1 x GAL 20V8-25) 6211 9.40 18.60

800535 assembler course(1 x EMON52 EPROM and1 x disk 1811) 6221 17.05 34.10Watt-hour meter (1 x 27256) 6241 10.00 20.00Four fold DAC (1 x GAL) 6251 10.75 21.50Multipurpose display decoder(1 x 2764) 6261 11.50 23.00Telephone -controlled switch(1 x 2764) 6271 14.50 29.00Relative humidity meter(1 x 2764) 6301 14.50 29.00535 card w. EPROM emulator(1 x PAL; 1 x GAL) 6311 26.00 52.00Copybit eliminator ( 1 x GAL16V8 and 1 x MACH110) 6321 42.25 84.50RDS decoder (1 x 27C64) 6331 14.50 29.0012C tester (1 x GAL 6001) 6341 30.75 61.508751 programmer (1 x 8751) 7061 46.40 92.80Microcontroller NiCd charger(1 x ST62E15) 7071 10.00 20.00Maxi micro clock (clock) 7081 11.50 23.00Maxi micro clock (darkroom timer) 7091 11.50 23.00Maxi micro clock (cooking timer) 7101 11.50 23.00Mini micro clock (clock) 7111 11.50 23.00Mini micro clock (darkroom timer) 7121 11.50 23.00Mini micro clock (cooking turner) 7131 11.50 23.00VHF/UHF TV tuner(1 x 87C51) 7141 25.75 51.50Microntroller-driven UART(1 x ST62T10) 7151 17.25 34.50PIC programmer(1 x PIC17C42 and 1 x disk) 7161 50.00100.00

DISKETTES

Plotter driver (D. Sijtsma) 1541 11.15 22.30I/O interface for Atari 1571 7.65 15.30Tek/Intel file converter 1581 7.65 15.30B/W video digitizer 1591 11.15 22.30Timecode interface 1611 7.65 15.30RTC for Atari ST 1621 7.65 15.3024 -bit colour extensionfor video digitizer 1631 11.15 22.30PC controlled weatherstation - 3 (supersedesdisks 1551 and 1561) 1641 7.65 15.308051/8032 Assembler course(IBM version) 1661 7.65 15.308051/8032 Assemblercourse (Atari version) (3.5") 1681 7.65 15.30AD232 converter 1691 7.65 15.30GAL programmer (3 disks;upgrade: June 1993) 1701 11 15 22.30

PROJECT No. Price Price(£) (US$)

Multi -purpose Z80 card 1711 7.65 15.30Fuzzy Control One 1721 7.75 15.50Pascal library for MMC 1751 9.70 19.40Speech/sound memory 1771 7.65 15.30PC -aided transistor tester 1781 7.50 15.00IR receiver and DIME decoderfor 80C32 SBC 1791 9.00 18.00800535 assembler course 1811 8.80 17.6012C opto/relay card 1821 7.65 15.30Video digitizer for PCs 1831 14.50 29.00GAL programmer for Amiga 1841 11.00 22.0012C alphanumerical display 1851 8.50 17.00Philips preamplifier 1861 8.50 17.00GAL programmer (excl. OpalJr. disks) 1881 10.75 21.50Precision clock for PCs 1871 8.50 17.00X2404 -to -8751 interfacing 1891 8.50 17.00Mini I/O card for CasioFX850/880P 1921 10.75 21.50SIM - an 8051 simulator 1931 34.25 68.50

PRINTED CIRCUIT BOARDS

Printed circuit boards whose number is followed by a+ sign are only available in combination with the as-sociated software item, and can not be supplied sepa-rately. The indicated price includes the software.

NOVEMBER 1993Fuzzy logic multimeter - 3(four boards)

Precision clock for PCsincl. disk (1871)

VHF/UHF TV tunerboards -1 and -2, and

87C51 (7141)Output amplifier with AFbandpass filterElectronic loadDigital hygrometerincl. EPROM (6301)

Power MOSFET tester

920049 Not available

930058+ 12.25 24.50

930064+ 57.25114.50

930071 6.75 13.50930088 Not available

930104+ 28.00 56.00930107 32.50 65.00

DECEMBER 1993535 card w. EPROM emulatorincl. GAL and PAL (6311) 930103+AF rms voltmeter 930108I2C power switch 930091Medium power HEXFETamplifier 930102Microcontroller driven UART 930073SCART switching box 930122Low -power NBFM transmitter 914114Photographic workshop light 930116Stereo PWM output amplifier 934076

47.5012.256.25

95.0024.5012.50

12.75 25.504.75 9.50

14.25 28.50Not availableNot availableNot available

JANUARY 1994Digital dialRDS decoderincl. EPROM (6331)12C testerincl. GAL (6341)

Telephone -controlled switchincl. EPROM (6271)

FEBRUARY 1994800535 single -boardcomputerCopybit eliminatorincl. MACH and GAL

930161

930121+

930128+

934054+

924046

930098+

12.75

23.75

36.25

37.25

14.10

46.25

25.50

51.50

72.50

74.50

28.20

92.50Mini preamplifierBidirectional RS232 -to -

930106 29.25 58.50

Centronics converter 930134 14.00 28.0024 cm FM ATV transmitter PCB available from author

MARCH 1994PIC programmerincl. software set 7161 940048+ 64.75129.50

100W AF amplifier- adaptor board 930039 8.25 16.50- amplifier board 920135-1 19.40 38.80- protection board 920135-2 7.95 15.90

Mini I/O card for CasioFX850/880P 930090 Not available

A list of all PCBs, software products and front panels available through the Readers Services ispublished in the March, June, September and December issues of Elektor Electronics.


xr

3-94Send this order form to "Elektor Electronics (Publishing)P.O. Box 1414Dorchester DT2 8YHENGLAND

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April /993

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The standard subscription order period is twelve months.If a permanent change of address during your subscrip-tion period means that copies have to be dispatched by amore expensive service, no extra charge will be made.Similarly, no refund will be made, norexpiry date extended,if a change of address allows the use of a cheaper service.

Student applications, which qualify for a 10% (ten percent) reduction in current rates, must be supported by ev-idence of studentship signed by the head of the college,school or university faculty.

Please note that new subscriptions take about four weeksfrom receipt of order to become effective.

Cancelled subscriptions will be subject to a charge of25% (twenty-five per cent) of the full subscription price or£7.50, whichever is the higher, plus the cost of any issuesalready dispatched. Subscriptions cannot be cancelled afterthey have run for six months or more.

Our bankers are National Westminster Bank PLC, SortingCode 60-03-23, 100 High Street, Brentford TW8 8AY,England. Our account number is 4285 0134.

June 1993

L



SURVEILLANC13PIU11ESSI4KAL 01JALIT7' KITS

No. I for KitsWhether your requirement for surveillance equipment is amateur, professional or you are just fascinated by this unique area ofelectronics SUMA DESIGNS has a kit to fit the bill. We have been designing electronic surveillance equipment for over 12 yearsand you can be sure that all our kits are very well tried, tested and proven and come complete with full instructions, circuitdiagrams, assembly details and all high quality components including fibreglass PCB. Unless otherwise stated all transmittersare tuneable and can be received on an ordinary VHF FM radio.

Genuine SUMA kits available only direct from Suma Designs. Beware inferior imitations!UTX Ultra -miniature Room TransmitterSmallest room transmitter kit in the word! Incredible 10mm x 20mm including mic.3-12V operation. 500m range £16.45

MTX Micro -miniature Room TransmitterBest-selling micro -miniature Room TransmitterJust 17mm x 17mm including mic. 3-12V operation. 1000m range £13.45

STX High-performance Room TransmitterHi performance transmitter with a buffered output stage for greater stability and range.Measures 22mm x 22mm including mic. 6-12V operation, 1500m range £15.45

VT500 High -power Room TransmitterPowerful 250mW output providing excellent range and performance. Size 20mm x40mm. 9-12V operation. 3000m range £16.45

VXT Voice Activated TransmitterTriggers only when sounds are detected. Very low standby current. Variable sensitivityand delay with LED indicator. Size 20mm x 67mm. 9V operation. 1000m range £19.45

HVX400 Mains Powered Room TransmitterConnects directly to 240V AC supply for long-term monitoring. Size 30mm x 35mm.500m range £19.45

SCRX Subcarrier Scrambled Room Transmitter

Scrambled output from this transmitter cannot be monitored without the SCDM decoderconnected to the receiver. Size 20mm x 67mm. 9V operation. 1000m range £22.95

SCLX Subcarrier Telephone TransmitterConnects to telephone line anywhere, requires no batteries. Output scrambled sorequires SCDM connected to receiver. Size 32mm x 37mm. 1000m range £23.95

SCDM Subcarrier Decoder Unit for SCRXConnects to receiver earphone socket and provides decoded audio output toheadphones. Size 32mm x 70mm. 9-12V operation £22.95

ATR2 Micro Size Telephone Recording InterfaceConnects between telephone line (anywhere) and cassette recorder. Switches tapeautomatically as phone is used. All conversations recorded. Size 16mm x 32mm.Powered from line £13.45

*** Specials ***OLTIUDLRX Radio Control SwitchRemote control anything around your home or garden, outside lights, alarms, pagingsystem etc. System consists of a small VHF transmitter with digital encoder and receiverunit with decoder and relay output, momentary or alternate, 8 -way dil switches on bothboards set your own unique security code. TX size 45mm x 45mm. RX size 35mm x90mm. Both 9V operation. Range up to 200m.Complete System (2 kits) £50.95Individual Transmitter DLTX £19.95Individual Receiver DLRX £37.95

MIX -1 11141 Micro BroadcasterNot technically a surveillance device but a great idea! Connects to the headphone outputof your Hi-Fi, tape or CD and transmits Hi-Fi quality to a nearby radio. Listen to yourfavourite music anywhere around the house, garden, in the bath or in the garage andyou don't have to put up with the DJ's choice and boring waffle. Size 27mm x 60mm.9V operation. 250m range £20.95

a

A

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UTLX Ultra -miniature Telephone TransmitterSmallest telephone transmitter kit available. Incredible size of 10mm x 20mm!Connects to line (anywhere) and switches on and off with phone use.All conversation transmitted. Powered from line. 500m range £15.95

TLX700 Micro -miniature Telephone TransmitterBest-selling telephone transmitter. Being 20mm x 20mm it is easier to assemble thanUTLX. Connects to line (anywhere) and switches on and off with phone use. Allconversations transmitted. Powered from line. 1000m range £13.45

STLX High-performance Telephone TransmitterHigh performance transmitter with buffered output stage providing excellent stabilityand performance. Connects to line (anywhere) and switches on and off with phone use.All conversations transmitted. Powered from line. Size 22mm x 22mm.1500m range £16.45

TKX900 Signalling/Tracking TransmitterTransmits a continous stream of audio pulses with variable tone and rate. Ideal forsignalling or tracking purposes. High power output giving range up to 3000m. Size25mm x 63mm. 9V operation £22.95

CD400 Pocket Bug Detector/LocatorLED and piezo bleeper pulse slowly, rate of pulse and pitch of tome increase as youapproach signal. Gain control allows pinpointing of source. Size 45mm x 54mm. 9Voperation £30.95

CD600 Professional Bug Detector/LocatorMulticolour readout of signal strength with variable rate bleeper and variable sensitivityused to detect and locate hidden transmitters. Switch to AUDIO CONFORM mode todistinguish between localised bug transmission and normal legitimate signals such aspagers, cellular, taxis etc. Size 70mm x 100mm. W operation £50.95

ammo Crystal Controlled Room transmitterNarrow band FM transmitter for the ultimate in privacy. Operates on 180 MHz andrequires the use of a scanner receiver or our QRX180 kit (see catlogue). Size 204a95mmx67mm. 9V operation. 1000m range £40.95

PLX180 Crystal Cointrolled Telephone TransmitterAs per QTX180 but connects to telephone line to monitor both sides of conversations.E4520mm x 67mm. 9V operation. 1000m range 0

IISX180 Line Powered Crystal Controlled Phone TransmitterAs per CILX180 but draws power requirements from line. No batteries required. Size32mm x 37mm. Range 500m £35.95

QUM Crystal Controlled FM ReceiverFor monitoring any of the 'Q' range transmitters. High sensitivity unit. All RF sectionsupplied as a pre -built and aligned module ready to connect on board so no difficultysetting up. Outpt to headphones. 60mm x 75mm. 9V operation £60.95

A build-up service is available on all our kits if required.UK customers please send cheques, POs or registered cash. Please add£1.50 per order for P&P. Goods despatched ASAP allowing for chequeclearance. Overseas customers send sterling bank draft and add £5.00 perorder for shipment. Credit card orders welcomed on 0827 714476.

OUR LATEST CATALOGUE CONTAINING MANY MORE NEWSURVEILLANCE KITS NOW AVAILABLE. SEND TWO FIRSTCLASS STAMPS OR OVERSEAS SEND TWO IRCS.

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74

ELEKTOR ELECTRONICS is available from, among others:

CRICKLEWOODELECTRONICS LIMITED40 Cricklewood Broadway,

London NW2 3ETTelephone 081 450 0995

Fax 081 208 1441

L.F. HANNEYYour electronic componentspecialist for Avon, Wilts &

Somerset.77 Lower Bristol Road, Bath,

Avon, Telephone 0225424811

AAGE NIELSEN1 Sortedam DosseringenDK-2200 Copenhagen,

Denmark,Telephone 01 39 30 10

Fax 031 39 05 02

TABACCARIA BRITANICAPraca do Duque da

Terceira 191107 Lisboa, PortugalTelephone 932 4752

MK KNJIGARNASlovenska 29

LjubljanaSlovenia

Telephone 061 150 196

THE ELECTRONIC SHOPElectronic components, test

equipment, telephoneaccessories, computer

accessories, microphones,disco lighting, speakers, turntables, mixers, meters, stylus.

29 Hanging Ditch,Manchester M4 3ES,

Telephone 061 834 1185

HELMHOLT ELEKTRONIKFarvevej 2

DK-7600 Struer, DenmarkTelephone 97 85 26 11

D.P. HOBBS (NORWICH)LTD

Electronic componentspecialists. Amateur radio

equipment.13 St. Benedict Street,

Norwich NR2 4PE,Telephone 0603 615786

RCE ELECTRONICCENTRE

Boulevarden 34DK-9000 Aalborg, Denmark

Telephone 98 16 07 10

TECHNICAL BOOKS &MAGAZINES

289-299 Swanston StreetMelbourne, Australia 3000

Telephone 663 3951MANCOMP

240 Platt LaneManchester M14 7BS

EnglandTelephone 061 224 1888

GREENWELD27 Park Road

Southampton SO1 3TBEngland

Telephone (0703) 236 363Fax (0703) 236 307

VEJLE RC ELEKTRONIKSdr Brogade 42

P 0 Box 332DK-7100 Vejle, DenmarkTelephone 75 83 25 33

INEL Co.P.O. Box 1397

JL. Hariang Banga No. 3Bandung 40116

IndonesiaOMNI ELECTRONICSStock a wide range of

electronic components.174 Dalkeith Road,

Edinburgh EH16 5DX,Telephone 031 667 2611

BEBEK ELECTRONICSHirsimetsantie 26SF -15200 Lahti 11

FinlandTelephone (18) 33 99 46

Advertising Standards AuthorityBadger BoardsB K ElectronicsBull ElectricalCanal Bridge AudioCILCirkit DistributionCricklewood ElectronicsDisplay ElectronicsElectronics - the Maplin MagazineElectroValueElektor ElectronicsElinge Komponent ServiceESR Electronic ComponentsIce Technologylnstrutek (UK)J P DistributionLabcenterMaplin Electronic SuppliesMicroAmpsMorrison MicrosNumber One Systems LtdPico Technology LtdPOWERwareSpeaker BuilderSquarewave ElectronicsStewart of Reading

INDEX OF ADVERTISERS

3364

40, inside back cover545559

41

33

243933

38, 58, 7464

25

Inside front cover55

5929

Back cover41

644

4937

33

59

41

Swift Television PublicationsSuma DesignsThose EngineersTsien (UK) LtdViewcom ElectronicsWhite House Systems

ADVERTISING SPACEfor the April 1994 issue may be reserved not later thanThursday 10 February 1994 by

Elektor Electronics (Publishing)Advertisement Office

3 Crescent TerraceCheltenham GL50 3PE

EnglandTelephone (0242) 510 760

Fax (0242) 226 626

37

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to whom all correspondence, copy instructions and artworkshould be addressed.



POWER AMPLIFIER MODULES -TURNTABLES -DIMMERS -LOUDSPEAKERS -19 INCH STE ED

R U. -SERVICE * LARGE CA41 60p STAMPED FOR CATALOGUE *

OMP MOS-FET POWER AMPLIFIERSHIGH POWER, TWO CHANNEL 19 INCH RACK

THOUSANDS PURCHASEDBY PROFESSIONAL USERS

THE RENOWNED MXF SERIES OF POWER AMPLIFIERSFOUR MODELS:- MXF200 (100W + 100W) MXF400 (200W + 200W)

MXF600 (300W + 300W) MXF900 (450W + 450W)ALL POWER RATINGS R.M.S. INTO 4 OHMS, BOTH CHANNELS DRIVEN

FEATURES: *Independent power supplies with two toroidal transformers * Twin L E D Vu meters *Level controls * Illuminated gala switch * XLR connectors * Standard 775mV inputs * Open and short circuitproof * Latest Mos-Fets for stress free power delivery into virtually any load * High slew rate * Very lowdistortion * Aluminium cases * MXF600 & MXF900 fan cooled with D C loudspeaker and thermal protection

USED THE WORLD OVER IN CLUBS, PUBS, CINEMAS, DISCOS ETCSIZES:- MXF200W19'xH3',e" (2U)xD11"

MXF400 W 19"x145'4" (3U)x131 2"MXF600W19"xH5'," (3U)vD13"MXF900 W19"x115',." (3U)xD14.,t"

PRICES:-MXF200 £175.00 MXF400 £233.85MXF600 £329.00 MXF900 £449 15SPECIALIST CARRIER DEL. F12.50 EACH

Advanced 3 -Way Stereo Active Cross -Over, housed in a 19' x 1U case Each channel has three level controlsbass, mid & top. The removable front fascia allows access to the programmable DIL switches to adjust thecross -over frequency: Bass -Mid 250/500/800Hz, Mid Top 1 8/3/5KHz, all at 24dB per octave Bass invert switcheson each bass channel. Nominal 775mV input/output Fully compatible with OMP rack amplifier and modules

Price £117.44 + £5.00 P&P, I t =I :1=1.7 I< I 41-1= * ECHO & SOUND EFFECTS*

STEREO DISCO MIXER with 2 x 7 bandL & R graphic equalisers with bar graphLED Vu meters. MANY OUTSTANDINGFEATURES:- including Echo with repeat &speed control, DJ Mic with talk -overswitch, 6 Channels with individual fadersplus cross fade, Cue Headphone Monitor. 8Sound Effects. Useful combination of thefollowing inputs:- 3 turntables (mag), 3mica, 5 Line for CD, Tape, Video etc.

Price £144.99 + £5.00 P&P SIZE: 482 x 240 x 120mm

1;t1"1 Illjf1 al1.111111441 SUPPLIED READY BUILT AND TESTED.These modules now enjoy a world-wide reputation for quality, reliability and performance at a realistic price. Fourmodels are available to suit the needs of the professional and hobby market i.e. Industry, Leisure. Instrumental and Hi-Fietc. When comparing prices, NOTE that all models include toroidal power supply, integral heat sink, glass fibre P.C.B. anddrive circuits to power a compatible Vu meter. All models are open and short circuit proof.

THOUSANDS OF MODULES PURCHASED BY PROFESSIONAL USERSOMP/MF 100 Mos-Fet Output power 110 wattsR.M.S. into 4 ohms, frequency response 1Hz - 1 OOKHz-3dB, Damping Factor > 300, Slew Rate 45ViuS,T.H.D. typical 0.002%, Input Sensitivity 500mV, S.N.R.-110 dB. Size 300 x 123 x 60mm.PRICE £40.85 - £3.50 P&P

s

OMP/MF 200 Mos-Fet Output power 200 wattsR.M.S. into 4 ohms, frequency response 1Hz - 1 OOKHz-3dB, Damping Factor > 300, Slew Rate 50VIuS,T.H.D. typical 0.001%, Input Sensitivity 500mV, S.N.R.-110 dB. Size 300 x 155 x 100mm.PRICE £64.35 + £4.00 P&P

OMP/MF 300 Mos-Fet Output power 300 wattsR.M.S. into 4 ohms, frequency response 1Hz - 100KHz-3dB, Damping Factor > 300, Slew Rate 60V/uS,T.H.D. typical 0.001%, Input Sensitivity 500mV, S.N.R.-110 dB. Size 330 x 175 x 100mm.PRICE £81.75 £5.00 P&P

OMP/MF 450 Mos-Fet Output power 450 wattsR.M.S. into 4 ohms, frequency response 1Hz - 100KHz-3dB, Damping Factor , 300, Slew Rate 75V/uS,

104 T.H.D. typical 0.001%, Input Sensitivity 500mV, S.N.R.-110 dB, Fan Cooled, D.C. Loudspeaker Protection, 2Second Anti -Thump Delay. Size 385 x 210 x 105mm.PRICE £132.85 + £5.00 P&P

OMP/MF 1000 Mos-Fet Output power 1000 wattsR.M.S. into 2 ohms, 725 watts R.M.S. into 4 ohms,frequency response 1Hz - 100KHz -3dB, DampingFactor > 300, Slew Rate 75V/uS, T.H.D. typical0.002%, Input Sensitivity 500mV, S.N.R. -110 dB, FanCooled, D.C. Loudspeaker Protection, 2 SecondAnti -Thump Delay. Size 422 x 300 x 125mm.PRICE £259.00 + £12.00 P&P

NOTE: MOS-FET MODULES ARE AVAILABLE IN TWO VERSIONS:STANDARD - INPUT SENS 500mV, BAND WIDTH 100101x.PEC (PROFESSIONAL EQUIPMENT COMPATIBLE) - INPUT SENS775mV, BAND WIDTH SOKHz. ORDER STANDARD OR PEC.

: it :

Join the Piezo revolution! The low dynamic mass (no voice coil) of a Piezo tweeter produces an improvedtransient response with a lower distortion level than ordinary dynamic tweeters. As a crossover is not requiredthese units can be added to existing speaker systems of up to 100 watts (more if two are put in series. FREEEXPLANATORY LEAFLETS ARE SUPPLIED WITH EACH TWEETER.

TYPE 'A' (KSN1036A) 3" round with protective wire mesh. Ideal forbookshelf and medium sized Hi-Fi apeakers. Price £4.90 + 50p P&P.TYPE 'B' (KSN1005A) 3'/" super horn for general purpose speakers,disco and P.A. systems etc. Price £5.99 + 50p P&P.TYPE 'C' (KSN1016A) 2"x5" wide dispersion horn for quality Hi-Fi sys-tems and quality discos etc. Price £6.99 - 50p P&P.TYPE '0' (KSN1025A) 2"x6" wide dispersion horn. Upper frequencyresponse retained extending down to mid -range (2KHz). Suitable for highquality Hi-Fi systems and quality discos. Price £9.99 r 50p P&P.TYPE 'E' (KSN1038A)31'." horn tweeter with attractive silver finish trim.Suitable for Hi-Fi monitor systems etc. Price £5.99 -r 50p P&P.LEVEL CONTROL Combines, on a recessed mounting plate, level controland cabinet input jack socket. 85x85mm. Price £4.10 + 50p P&P.

lb/ FLIGHT CASED LOUDSPEAKERSA new range of quality loudspeakers, designed to take advantage of the latestspeaker technology and enclosure designs. Both models utilize studio quality12" cast aluminium loudspeakers with factory fitted grilles, wide dispersionconstant directivity horns, extruded aluminium corner protection and steelball corners. complimented with heavy duty black covering. The enclosuresare fitted as standard with top hats for optional loudspeaker stands.

POWER RATINGS QUOTED IN WATTS RMS FOR EACH CABINETFREQUENCY RESPONSE FULL RANGE 45Hz - 20KHz

ibl FC 12-100WATTS (100dB) PRICE £159.00 PER PAIRibt FC 12-200WATTS (100dB) PRICE £175.00 PER PAIR

SPECIALIST CARRIER DEL. £12.50 PER PAIR

OPTIONAL STANDS PRICE PER PAIR £49.00Delivery £6.00 per pair

LOUDSPEAKER LARGE SELECTION OF SPECIALIST LOUDSPEAKERSAVAILABLE, INCLUDING CABINET FITTINGS, SPEAKERGRILLES, CROSS-OVERS AND HIGH POWER, HIGHFREQUENCY BULLETS AND HORNS, LARGE (A4) S.A.E.(60p STAMPED) FOR COMPLETE LIST.

McKenzie and Fane Loudspeakers are also available.

EMINENCE:- INSTRUMENTS, P.A., DISCO, ETC

ALL EMINENCE UNITS El OHMS IMPEDANCE8" 100 WATT R.M.S. ME8-100 GEN. PURPOSE, LEAD GUITAR, EXCELLENT MID, DISCO.RES. FRED. 72Hz, FRED. RESP. TO 4KHz, SENS 97dB. PRICE £32.71 - C2.00 P&P10" 100 WATT R.M.S. MEI 0-100 GUITAR, VOCAL, KEYBOARD, DISCO, EXCELLENT MID.RES. FREQ. 71Hz, FREQ. RESP. TO 7KHz, SENS97dB. PRICE C33.74 + £2.50 P&P10" 200 WATT R.M.S. ME10-200 GUITAR, KEYB'D, DISCO, VOCAL, EXCELLENT HIGH POWER MID.RES. FREQ. 65Hz, FREQ. RESP. TO 3.5KHz, SENS 99dB. PRICE C43.47 - C2.50 P&P12" 100 WATT R.M.S. ME12-100LE GEN. PURPOSE, LEAD GUITAR, DISCO, STAGE MONITOR.RES.FRED. 49Hz, FRED. RESP. TO 6KHz, SENS 100dB. PRICE £35.64 + £3.50 P&P12" 100 WATT R.M.S. ME12-100LT (TWIN CONE) WIDE RESPONSE, P.A., VOCAL, STAGEMONITOR. RES. FRED 42Hz, FREQ. RESP. TO 10KHz, SENS 98dB. PRICE £36.67 h 03.50 P&P12" 200 WATT R.M.S. ME12-200 GEN. PURPOSE, GUITAR, DISCO, VOCAL, EXCELLENT MID.RES. FREQ. 58Hz, FRED. RESP. TO 6KHz, SENS 98dB. PRICE £46.71 I £3.50 P&P12" 300 WATT R.M.S ME12-300GP HIGH POWER BASS, LEAD GUITAR, KEYBOARD, DISCO ETC.RES. FRED. 47Hz, FREQ. RESP. TO 5KHz, SENS 103dB. PRICE £70.19 + £3.50 P&P15" 200 WATT R.M.S. ME15-200 GEN. PURPOSE BASS, INCLUDING BASS GUITAR.RES. FRED. 46Hz, FRED. RESP. TO 5KHz, SENS 99dB. PRICE £50.72 £4.00 P&P15" 300 WATT R.M.S. ME15-300 HIGH POWER BASS, INCLUDING BASS GUITAR.RES. FREQ. 39Hz, FREQ. RESP. TO 3KHz, SENS 103dB. PRICE C73.34 -r C4.00 P&P

EARBENDERS:- HI-FI, STUDIO, IN -CAR, ETCALL EARBENDER UNITS 8 OHMS (Except EB8-50 & EB10-50 which are dual impedance tapped a 4 & 8 ohm)BASS, SINGLE CONE, HIGH COMPLIANCE, ROLLED SURROUND8" 50watt EB8-50 DUAL IMPEDENCE, TAPPED 4/8 OHM BASS, HI-FI, IN -CAR.RES. FREQ. 40Hz, FREQ. RESP. TO 7KHz SENS 97dB. PRICE C8.90 - C2.00 P&P10" 50WATT EB10-50 DUAL IMPEDENCE, TAPPED 4/8 OHM BASS, HI-FI, IN -CAR.RES. FREQ. 40Hz, FRED. RESP. TO 5KHz, SENS. 99dB. PRICE £13.65 £2.50 P&P10" 100WATT EB10-100 BASS, HI-FI, STUDIO.RES. FREQ. 35Hz, FREQ. RESP. TO 3KHz, SENS 96dB. PRICE £30.39 I £3.50 P&P12" 1 00WATT EB12-100 BASS, STUDIO, HI-FI, EXCELLENT DISCO.RES. FREQ. 26Hz, FREQ. RESP. TO 3KHz, SENS 93dB. PRICE C42.12 I- £3.50 P&PFULL RANGE TWIN CONE, HIGH COMPLIANCE, ROLLED SURROUND

60WATT EB5-60TC (TWIN CONE) HI-FI, MULTI -ARRAY DISCO ETC.RES. FRED. 63Hz, FRED. RESP. TO 20KHz, SENS 92dB. PRICE £9.99 I- C1.50 P&P6'I2" 60WATT EB6-60TC (TWIN CONE) HI-FI, MULTI -ARRAY DISCO ETC.RES. FRED. 38Hz, FREQ. RESP. TO 20KHz, SENS 94dB. PRICE £10.99 1.50 P&P8" 60WATT EB8-60TC (TWIN CONE) HI-FI, MILTI-ARRAY DISCO ETC.RES. FRED. 40Hz, FRED. RESP. TO 18KHz, SENS 89d13. PRICE £12.99 + £1.50 P&P10" 60WATT EB10-60TC (TWIN CONE) HI-FI, MULTI ARRAY DISCO ETC.RES. FRED. 35Hz, FRED. RESP. TO 12KHz, SENS 98dB. PRICE £16.49 - £2.00 P&P

PRICES, 150W £49.99 250W £99.99400W £109.95 P&P £2.00 EACH

THREE SUPERB HIGH POWERCAR STEREO BOOSTER AMPLIFIERS150 WATTS (75 75) Stereo, 150WBridged Mono250 WATTS (125 I 125) Stereo, 250WBridged Mono400 WATTS (200 x 200) Stereo, 400WBridged MonoALL POWERS INTO 4 OHMSFeatures:* Stereo, bridgable mono * Choice ofhigh & low level inputs * L & R levelcontrols * Remote on -off * Speaker &thermal Drotectio

PROVEN TRANSMITTER DESIGNS INCLUDING GLASS FIBREPRINTED CIRCUIT BOARD AND HIGH QUALITY COMPONENTS

COMPLETE WITH CIRCUIT AND INSTRUCTIONS3W TRANSMITTER 80-108MHt, VARICAP CONTROLLED PROFESSIONAL s

PERFORMANCE, RANGE UP T03 MILES, SIZE 38 x 123mm. SUPPLY 12V a 0.5AMP.

PRICE (14.85 - £1.00 P&PFM MICRO TRANSMITTER 100.108MHx, VAMP TUNED, COMPLETE WITHVERY SENS FET MIC, RANGE 100-300m, SIZE 56 x 46mm. SUPPLY 9V BATTERY.

;1 t s s PHOTO: 3W FM TRANSMITTER

B.K. ELECTRONICSPOSTAL CHARGES PER ORDER E.1.00 MINIMUM. OFFICIAL BARORDERS FROM SCHOOLS, COLLEGES, GOVT. BODIES, PLCes ETC.PRICES INCLUSIVE OF V.A.T. SALES COUNTER. VISA AND

ACCESS ACCEPTED BY POST, PHONE OR FAX.


UNITS 1 & 5 COMET WAY, SOUTHEND-ON-SEA,ESSEX. SS2 ETR.

Tel.: 0702 - 527572 Fax.: 0702 - 420243

FULL COLOUR GUIDE TO ELECTRONIC PRODUCTS

Aneno

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BS 5750Part 2 1987

Level B:Duality Assurance

RS12750

Over 700 colour packed pages with hundredsof brand New Products at Super Low Prices-,`

on sale now onl £2.95.Available from all branches of WHSMITH, selected branches of

RsmccoLL in Scotland ONLY, and Maplin stores nationwide.The Maplin Electronics 1994 Catalogue - UNIQUELY DIFFERENT!

Africa customers please contact MAPLIN (SOUTH AFRICAITel (0241 5 1-5 124

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