lab instruction

7/30/2019 Lab Instruction

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LABORATORY SCHEDULESession 2012/ 2013

Semester I

Should you have any enquiries, please contact:JKEES Office : 03-89118393

2nd Year Laboratory : 03-89216319

Week Mon Tue Wed Thu Fri Sat Sun

110Sept 11 12 13 14 15 16

217 18 19 20 21 22 23

324 * Lab

begin25 26 27 28 29 30

41 Okt 2 3 4 5 6 7

58 9 10 11 12 13 14

615 16 17 18 19 20 21

722 23 24 25 26 27 28

829 30 31 1 Nov 2 3 4

95 6 7 8 9 10 11

Mid Sem

Break

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1020 21 22 23 24 25 26

1127 28 29 30 1 *Dis 2 3

124 5 6 7 8 9 10

1311 12 13 14 15 16 17

1418 19 20 21 22 23 24

15Study week

25 26 27 28 29 30 31

16Exams

1*Jan 2 3 4 5 6 7

17Exams

8 9 10 11 12 13 14

18Exams

15 16 17 18 19 20 21


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INTRODUCTION TO LAB WORK STATION

AND ELECTRONICS COMPONENTS

Hilmi SanusiJKEES

Introduction

This is an introduction to the instruments that you will be using for all your laboratory

experiment in first and second year, including your Digital Electronics lab and Micro Processor

lab. The instruction given in this manual will cover steps that should be taken in order to

conduct successful experiment. This manual will introduce you to all equipments first, then a

specific instruction for analog and digital lab procedures. For every student workbench, you may

find these instruments;

(a) IDL Experiment station (b) Oscilloscope

(c) Function generator (d) Digital Multimeter

Figure 1. Typical equipments on the workbench

You can also find these equipments somewhere in your lab that will assist you to obtain better

results.

(a) LCR meter and IC tester (b) Curve tracerFigure 2. Test equipment available in the lab


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Before you can conduct any experiment, you must familiarize with the equipment that you will

be using. You must also know how to make all connections using the breadboard. We will start

with the IDL station. There are several key features that you need to know for the digital lab.

Figure 3. IDL Digital Trainer

You can find both analog and digital oscilloscope in the lab. However, only digital scope will be

provided for the student. Currently, we are using Tetronix TDS 220 since the scope is self

calibrated and auto triggered. The oscilloscope is a two channel with maximum frequency of 20

MHz.

Figure 4. Oscilloscope

There are several series of function generator in the lab. The models that you can find are

Tektronix, Amrel, Topward and IWATSU. The functionality and capability of the functiongenerator depends on the model used. In general, all of the function generator must be able to

generate sinusoidal, triangle and rectangular wave. Some will have attenuation function, offset,

frequency counter and others. Tetronix and Amrel have an auxiliary input to change the time

base in which can be used to generate Amplitude Modulation (AM). Different model will also

produce different quality of signal at low amplitude. You have to make sure that the signal

produced is above the noise threshold level. Below are some the Function Generator that you

can find in the lab.

Power switch

+/- 5V

0V +15V

-15V 0V

7 Segments Display

Function generator

Input 1 & 2

Voltmeter

Output Display

Digital inputGnd (Logic 0)

Power switch

Logic Pulsar

Aux Input

Test point

Autoset

SSD Dip switch


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(a) (b)

(c) (d)Figure 5. Function Generator (a) Tetronix, (b) Iwatsu, (c) Topward and (d) Amrel.

In order for you to have more precise experiment, there is several test equipment that you can

use. You can ask for a handheld multimeter or there are several bench-top multimeter available.

Fluke has more function and better precision than Topward. You can measure rms power for an

ac signal and perform nulling for the ohm meter. The RLC meter is able to measure the Q factor,

DCR for capacitor and series resistance for inductor besides the resistance, inductance and

capacitance. The IC tester is able to identify the logic gate and indicate the state of condition for

the logic gate. In the lab, you can also use the Hameg curve tracer to test the IV characteristic of

a diode and a transistor.

(a) Fluke (b) TopwardFigure 6. Benchtop Digital Multimeter

(a) LCR Meter (b) IC tester (c) Curve TracerFigure 7. Test equiptment

Sometimes, you might need to use a variable resistor, variable capacitor or variable inductor in

your experiment. In the lab, there are several types of variable passive device that you can use.


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Most of the variable passive device is in decade step in such a way that you can have any value

that you need. But some is just a single step.

(a) Decade Resistance Box (b) Variable Capacitance Box

Figure 8. Variable Passive Components

Familiarize with your Equipment

Your oscilloscope has three major sections, vertical, horizontal and trigger control. Each of the

section has its own function, which can be used to control, lock, amplify etc.

Vertical Control

The elements of the vertical section

POSITION knob Ch1/Ch2The POSITION knob is used to position a wave-form vertically on the

display.

Ch1/Ch2 MenuThese buttons open the Vertical Control menu for Ch1 or Ch2 on the

right side in the display. (description see below) If the menu is already

open this channel is switched o_ or on, depending on the former state.

MATH MENUDisplays waveform math operations menu and can also be used to

toggle the math waveform on and off. (Not used in the moment)

VOLTS/DIV knob Ch1/Ch2The VOLTS/DIV knob is used to modify the calibration of the vertical scale of the channel. In

other words, the VOLTS/DIV knob allows you to increase or decrease the vertical resolution

of a displayed waveform.

Input BNC-connector Ch1/Ch2Connectors for the input signal. Keep in mind that the ground of these plugs is

connected together and both are connected to PE of the power plug! That

means you only can measure related to a common ground. This is the Vertical

Control side screen menu switched on with the Ch1/2 menu button.

Coupling - DC, AC, Ground BW Limit - Bandwidth Limit On, Off Volts/Div - Coarse, Fine Probe - 1x, 10x, 100x, 1000x Invert - On, Off


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The buttons on the right of the screen beside the shown items scroll or select the different

menu items.

Measure Voltage using the cursors

With older analog scopes counting graticules was the way to get the values! In our

case we can use cursors to mark points of interest on the screen. The voltage at

the position of the cursor is then shown on the display. First an introduction to the

cursor menu:

This is the side screen menu when pushing the CURSOR knob:

Type - Off, Voltage, Time Source - CH1, CH2, MATH, REF A, REF B Delta Cursor 1 Cursor 2

The Type and Source items are switched with the buttons on the right of the screen. The other

positions are displays for the values! To move the cursors use the POSITION knobs from the

VERTICAL section. (Cursor 1 with CH1, Cursor 2 with CH2). In general the cursors measure

relative to the ground marker. They only can measure parts of a signal which are visible on the

screen inside the grid!

Switching the Input Coupling

In our case we have a mixed signal, a DC voltage with a small sine wave (AC voltage) on top. If

you want to increase the resolution of the AC part of the signal it is mostly impossible toincrease the range because in this case the wanted part of the curve is outside the screen.

Sometimes you can use the POSITION knob or the FINE resolution but especially with very small

AC components this is not possible. So we use AC-Coupling to remove the DC part of the signal

and increase the resolution of the sine. Coupling is the method to connect an electrical signal to

the oscilloscope. You can select AC, DC, or Ground coupling on the oscilloscope.


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The different settings have the following effects:

AC coupling blocks the DC component of a signal and displays only the AC component ofthe waveform, centered around zero volts. But be careful; in case of a small frequency it

affects your measurements!

DC coupling displays the entire signal. Ground coupling disconnects the signal from the vertical scale and displays a horizontal

line at zero volts.

Horizontal ControlThe elements of the horizontal section

POSITION knobAdjusts the horizontal position of all channels and math waveforms. The

resolution of this control varies with the time base.

HORIZONTAL MENU buttonDisplays the horizontal menu

SEC/DIV knobSelects the horizontal time/div (scale factor) for the main or the window

time base. When Window Zone is enabled, it changes the width of the

window zone by changing the window time base.

Trigger Section

The elements of the trigger section

LEVELThis control sets the amplitude level the signal must cross to cause an

acquisition.(i.e. make the scope start to record the signal)

TRIGGER MENUDisplays the trigger menu.

SET LEVEL TO 50%The trigger level is set to the vertical midpoint between the peaks of

the trigger signal.

FORCE TRIGGERStarts an acquisition regardless of an adequate trigger signal. This

button has no effect if the acquisition is already stopped.

TRIGGER VIEWDisplays the trigger waveform in place of the channel waveform whilethe TRIGGER VIEW button is held down. You can use this to see how

the trigger settings affect the trigger signal, such as trigger coupling.

Input EXT TRIGGERInput for an extra trigger signal.


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Probe Compensation

If you want to use the probe with 10x magnification you need to adjust the frequency response.

When you attach a passive voltage attenuation probe to an oscilloscope, the capacitances of

both the probe cable and the oscilloscope's input are combined. This combined capacitance

must match the capacitance of the input attenuation circuit of the probe. You must balance

these capacitive effects between the probe and oscilloscope.

Probes are designed to match the inputs of specific oscilloscope models. However, there are

slight variations between oscilloscopes and even between different input channels in an

oscilloscope. To minimize these variations, attenuating passive probes (10X and 100X probes)

have built-in compensation networks. You need to adjust this network to compensate the probe

for the oscilloscope channel that you are using. Note: If you use attenuation (only then!) youmust compensate a passive voltage attenuation probe every time you change a probe/channel

connection on your oscilloscope. This ensures that the probe accurately transfers the signal

from a signal source to the oscilloscope. The following procedure enables you to balance the

capacitive and resistive effects of a probe by compensation.

Get To Know Your Components

RESISTOR

Resistors restrict the flow of electric current and non-directional, you can plug them in either

way. They are not damaged by heat when soldering. Resistance is measured in ohms, the

symbol for ohm is an omega ().

1 is quite small so resistor values are often given in k and M .

1 k = 1000 and 1 M = 1000000 .

Resistor values are normally shown using coloured bands. Each colour represents a number.

Most resistors have 4 bands:


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The first band gives the first digit. The second band gives the second digit. The third band indicates the number of

zeros.

The fourth band is used to shows thetolerance (precision) of the resistor, this

may be ignored for almost all circuits

For a small value resistors (less than 10 ohm), the standard colour code cannot show values of

less than 10. To show these small values two special colours are used for the third band: gold

which means 0.1 and silver which means 0.01. The first and second bands represent the

digits as normal.

Real resistor values (the E6 and E12 series)

Resistors are not available with every possible value; you can find 22k and 47k but not 25k and50k. The standard resistor values are based on this idea and they form a series which follows the

same pattern for every multiple of ten. The E6 series (6 values for each multiple of ten, for

resistors with 20% tolerance). 10, 15, 22, 33, 47, 68, ... then it continues 100, 150, 220, 330, 470,

680, 1000 etc. For this series the step (to the next value) is roughly half the value. The E12 series

(12 values for each multiple of ten, for resistors with 10% tolerance). 10, 12, 15, 18, 22, 27, 33,

39, 47, 56, 68, 82, ... then it continues 100, 120, 150 etc. The E12 series is the one most

frequently used for resistors. It allows you to choose a value within 10% of the precise value you

need. This is sufficiently accurate for almost all projects and it is sensible because most resistors

are only accurate to 10% (called their 'tolerance'). For example a resistor marked 390 could

vary by 10% 390 = 39 , so it could be any value between 351 and 429 ..

Power Ratings of Resistors

Electrical energy is converted to heat when current flows through a resistor. Usually the effect is

negligible, but if the resistance is low a large current may pass making the resistor become

noticeably warm. The resistor must be able to withstand the heating effect and resistors have

power ratings to show this. the standard power ratings of 0.25W or 0.5W are suitable. The

power, P, developed in a resistor is given by:

P = I R

or

P = V / R

where:

P = power developed in the resistor in watts (W)

I = current through the resistor in amps (A)

R = resistance of the resistor in ohms ( )

V = voltage across the resistor in volts (V)

Examples:

A 470 resistor with 10V across it, needs a power rating P = V/R = 10/470 = 0.21W. In this case a

standard 0.25W resistor would be suitable.

A 27 resistor with 10V across it, needs a power rating P = V/R = 10/27 = 3.7W.


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A high power resistor with a rating of 5W would be suitable.

The bins in the back of the lab have the resistor value marked on each drawer. You can verify

the value by reading the color code on the resistor and use your RLC or multimeter to measureit. (This is important as resistors often get into the wrong bins, causing problems for the unwary

student).

Variable resistors

Variable resistorsconsist of a resistance track with connections at both ends and

a wiper which moves along the track as you turn the spindle. The track may be

made from carbon, cermet (ceramic and metal mixture) or a coil of wire (for low

resistances). The track is usually rotary but straight track versions, usually called

sliders, are also available.

Variable resistors may be used as a rheostat with two connections (the wiper andjust one end of the track) or as a potentiometer with all three connections in use.

Miniature versions called presets are made for setting up circuits which will not

require further adjustment. Sometimes, variable resistors are also called

potentiometers. They are specified by their maximum resistance, linear or

logarithmic track, and their physical size. Linear (LIN) track means that the

resistance changes at a constant rate as you move the wiper. Logarithmic (LOG)

track means that the resistance changes slowly at one end of the track and rapidly

at the other end, so halfway along the track is not half the total resistance.

CAPACITORSCapacitors are energy storage devices, means they store electric charge. Some are directional,

some are not. If directional, there is usually a plus sign in the diagram and devices will have a

plus or minus label on one wire (lead); if not, you can connect the device into your circuit either

way. While resistors all seem to look alike, capacitors take a wide variety of shapes and sizes.

Look in the bins in the back of the lab to acquaint yourself with these devices. The labeling of

value also varies considerably between type (material used) and manufacturer. Capacitors are

used in filter circuits because they easily pass AC (changing) signals but they block DC (constant)

signals. Sometimes, they are used with resistors in timing circuits because it takes time for a

capacitor to fill with charge. They are used to smooth varying DC supplies by acting as a

reservoir of charge.

Capacitance is a measure of a capacitor's ability to store charge. A large capacitance means that

more charge can be stored. Capacitance is measured in farads, symbol F. However 1F is very

large, so prefixes are used to show the smaller values. Three prefixes (multipliers) are used,

(micro), n (nano) and p (pico):

means 10-6 (millionth), so 1000000F = 1F

n means 10-9 (thousand-millionth), so 1000nF = 1F

p means 10-12(million-millionth), so 1000pF = 1nF


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There are many types of capacitor but they can be split into two groups, polarised and

unpolarized. Each group has its own circuit symbol and come in two different form; axial where

the leads are attached to each and radial where both leads are at the same end. Also note the

voltage rating of the capacitor.

Polarized Capacitor

Electrolytic capacitors are polarized and they must be connected the correct way round, at least

one of their leads will be marked + or -, else the capacitor might leak or explode. You have to be

very careful when connecting polarized capacitor. Also make sure that you choose your

capacitor to be at higher rating than operating voltage. A 25V is a sensible minimum for most

battery circuits. Tantalum bead capacitors are also polarised. They have low voltage ratings like

electrolytic capacitors indeed expensive but very small, so they are used where a large

capacitance is needed in a small size.

Unpolarized capacitors (small values, up to 10F)

Small value capacitors are unpolarized and may be connected either

way round. They are many types of unpolarized capacitor depending

on their dielectric and the way they are constructed. The stability of

the dielectric will determine the tolerance, whereas the type of

construction determines the voltage rating. Silver-mica, Teflon, polystyrene is the small

tolerance. Paper in oil, polyethylene, polycarbonated has bigger tolerance but available in large

value up to about 10 F. They are not damaged by heat when soldering, except for one unusual

type (polystyrene).

Many small value capacitors have their value printed but without a multiplier.

For example 0.1 means 0.1F = 100nF.

Sometimes the multiplier is used in place of the decimal point:

For example: 4n7 means 4.7nF.

Capacitor Number Code

A number code is often used on small capacitors where printing is difficult:

the 1st number is the 1st digit, the 2nd number is the 2nd digit, the 3rd number is the number of zeros to give the capacitance in pF.

Ignore any letters - they just indicate tolerance and voltage rating.

For example: 102 means 1000pF = 1nF (not 102pF!)

For example: 472J means 4700pF = 4.7nF (J means 5% tolerance).

Real capacitor values (the E3 and E6 series)

Capacitors are not available with every possible value, just like resistor. 22F and 47F are

readily available, but not 25F and 50F. The E3 series (3 values for each multiple of ten). 10,

22, 47, ... then it continues 100, 220, 470, 1000, 2200, 4700, 10000 etc. The step size increases

as the value increases (values roughly double each time). The E6 series (6 values for each


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multiple of ten) 10, 15, 22, 33, 47, 68, ... then it continues 100, 150, 220, 330, 470, 680, 1000

etc. Notice how this is the E3 series with an extra value in the gaps. The E3 series is the one most

frequently used for capacitors because many types cannot be made with very accurate values.

Diodes

Diodes allow electricity to flow in only one direction. The arrow of the circuit

symbol shows the direction in which the current can flow. When a reverse

voltage is applied a perfect diode does not conduct, but all real diodes leak a

very tiny current of a few A or less. This can be ignored in most circuits

because it will be very much smaller than the current flowing in the forward direction. However,

all diodes have a maximum reverse voltage (usually 50V or more) and if this is exceeded the

diode will fail and pass a large current in the reverse direction, this is called breakdown.

Ordinary diodes can be split into two types: Signal diodes which pass small currents of 100mA or

less and Rectifier diodes which can pass large currents. In addition there are LEDs (which havetheir own page) and Zener diodes

Signal diodes (small current)

Signal diodes are used to process information (electrical signals) in circuits, so they are only

required to pass small currents of up to 100mA. General purpose signal diodes such as the

1N4148 are made from silicon and have a forward voltage drop of 0.7V. Germanium diodessuch

as the OA90 have a lower forward voltage drop of 0.2V and this makes them suitable to use in

radio circuits as detectors which extract the audio signal from the weak radio signal.

Protection diodes for relays

Signal diodes are also used to protect transistors and ICs from

the brief high voltage produced when a relay coil is switched off,

as in relay circuit. The diode will discharge the current produce

by the coil in the relay when it turns off. This prevents the

induced voltage becoming high enough to cause damage to

transistors and ICs.

Rectifier diodes (large current)

Rectifier diodes are used in power supplies to convert alternating current (AC) to direct current

(DC). They are also used elsewhere in circuits where a large current must pass through the

diode. All rectifier diodes are made from silicon and therefore have a forward voltage drop of

0.7V. There are several ways of connecting diodes to make a rectifier to convert AC to DC. The

bridge rectifier is one of them and it is available in special packages containing the four diodesrequired


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Zener diodes

Zener diodes are used to maintain a fixed voltage. They are designedto 'breakdown' in a reliable and non-destructive way so that they

can be used in reverse to maintain a fixed voltage across their

terminals. With a resistor connected in series limits the current flow

through the zener diode. Zener diodes can be distinguished from

ordinary diodes by their code and breakdown voltage which are printed on them. Zener diode

codes begin BZX. Or Their breakdown voltage is printed with V in place of a decimal point, so

4V7 means 4.7V for example.

Light Emitting Diodes (LEDs)

LEDs emit light when an electric current passes through them. LEDs must be connected the

correct way round, the diagram may be labelled a or + for anode and k or - for cathode. The

cathode is the short lead and there may be a slight flat on the body of round LEDs. If you can see

inside the LED the cathode is the larger electrode. sometimes your circuit will fail because you

have the LEDs in backwards LEDs can be damaged by heat when soldering, but the risk is small

unless you are very slow. LEDs are available in red, orange, amber, yellow, green, blue and

white. Blue and white LEDs are much more expensive than the other colours. The colour of an

LED is determined by the semiconductor material, not by the colouring of the 'package' (the

plastic body). LEDs are available in a wide variety of sizes and shapes. The 'standard' LED has a

round cross-section of 5mm diameter and 3mm.

Never connect an LED directly to a battery or power supply!It will be destroyed almost instantly

because too much current will pass through and burn it out. LEDs must have a resistor in series

to limit the current to a safe value, for quick testing purposes a 1k resistor is suitable for most

LEDs if your supply voltage is 12V or less. You can calculate the resistor based on:

R = (VS - VL) / I

VS = supply voltage

VL = LED voltage (usually 2V, but 4V for b lue and white LEDs)

I = LED current (e.g. 20mA), this must be less than IF max.


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You can connect LEDs in series. All the LEDs connected in series pass the same current so it is

best if they are all the same type. The power supply must have sufficient voltage to provide

about 2V for each LED. Connecting several LEDs in parallel with just one resistor shared betweenthem is generally not a good idea. If the LEDs require slightly different voltages only the lowest

voltage LED will light and it may be destroyed by the larger current flowing through it.

LED displays are packages of many LEDs arranged in a pattern, the most familiar pattern being

the 7-segment displays for showing numbers (digits 0-9). 7-segment displays is available in two

versions: Common Anode (SA) with all the LED anodes connected together and Common

Cathode (SC) with all the cathodes connected together. Letters a-g refers to the 7 segments, A/C

is the common anode or cathode as appropriate (on 2 pins).

Transistors

Transistors amplify current, means that they to amplify the small current

input from B to large current through C. In many circuits a resistor is used to convert the

changing current to a changing voltage, so the transistor is being used to amplify voltage. A

transistor may be used as a switch (either fully on with maximum current, or fully off with no

current) and as an amplifier (always partly on). The amount of current amplification is called the

current gain, symbol hFE. Transistors can be damaged by heat when soldering or by misuse in a

circuit.

There are two types of standard transistors, NPN and PNP, with

different circuit symbols. The leads are labelled base (B),

collector (C) and emitter (E). In addition to standard (bipolar

junction) transistors, there are field-effect transistors which are

usually referred to as FETs.

When current pass through a transistor, it produces heat. If you

find that a transistor is becoming too hot to touch, you must

use a different transistor with higher rating or use a heat sink.

Heat sinks are needed for power transistors because they pass

large currents. The heat sink helps to dissipate the heat by

transferring it to the surrounding air.


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Transistors have three leads which must be connected the correct way round. Please take care

with this because a wrongly connected transistor may be damaged instantly when you switch

on. The easiest way to find out the lead is by referring to the manufacturers catalog. If you

suspect that a transistor may be damaged there are two easy ways to test it.Use a multimeter or a simple tester (battery, resistor and LED) to check each pair of leads for

conduction. Set a digital multimeter to diode test and an analogue multimeter to a low

resistance range. Test each pair of leads both ways (six tests in total):

The base-emitter (BE) junction should behave like a diode and conduct one way only. The base-collector (BC)junction should behave like a diode and conduct one way only. The collector-emitter (CE) should not conduct either way.

Switches

Several terms are used to describe switch contacts:Pole - number of switch contact sets.

Throw - number of conducting positions, single or double.

Way - number of conducting positions, three or more.

Momentary - switch returns to its normal position when released.

Open - off position, contacts not conducting.

Closed - on position, contacts conducting, there may be several on positions.

Condition Type of switch Diagram

ON-OFF Single Pole, Single Throw = SPST

ON-OFF Push-to-make = SPST Momentary

ON-(OFF) Push-to-break = SPST Momentary

ON-ON Single Pole, Double Throw = SPDT

ON-OFF-ON SPDT Centre Off

Dual ON-OFF Double Pole, Single Throw (DPST)

Dual ON-ON Double Pole, Double Throw = DPDT

ON-OFF-ON DPDT Centre Off


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Special Switches

Push-Push Switch (e.g. SPST = ON-OFF)

Microswitch (usually SPDT = ON-ON)

Tilt Switch (SPST)

Reed Switch (usually SPST)

DIP Switch (DIP = Dual In-line Parallel)

Multi-way Switch

Relays

Relay is an electrically operated switch. Current flowing through the coil of therelay creates a magnetic field which attracts a lever and changes the switch

contacts. The coil current can be on or off so relays have two switch positions.

Relays allow one circuit to switch a second circuit which can be completely

separate from the first. There is no electrical connection inside the relay between the two

circuits, the link is magnetic and mechanical.


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Reed relays

Reed relays consist of a coil surrounding a reed switch. Reed switches are

normally operated with a magnet, but in a reed relay current flows through the

coil to create a magnetic field and close the reed switch. Reed relays generally

have higher coil resistances than standard relays

Connectors

There are several ways to connect from one electronic system to the other. Here are some of

the examples you will use or see in the lab.

4mm plugs, sockets and terminals

Light Dependent Resistor (LDR)

An LDR is an input transducer (sensor) which converts brightness (light) to resistance.

It is made from cadmium sulphide (CdS) and the resistance decreases as the

brightness of light falling on the LDR increases. An LDR may be connected either way

round and no special precautions are required when soldering.

PCB

terminal

block

Terminal block

Battery clips and holders

Crocodile clips

BNC plug


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Typical results for a standard LDR:

Darkness: maximum resistance, about 1M .

Very bright light: minimum resistance, about 100 .

Thermistor

A thermistor is an input transducer (sensor) which converts temperature (heat) to

resistance. Almost all thermistors have a negative temperature coefficient (NTC) which

means their resistance decreases as their temperature increases.

Typical resistance of thermistor:

Icy water 0C: high resistance, about 12k .

Room temperature 25C: medium resistance, about 5k .Boiling water 100C: low resistance, about 400 .

Piezo transducer

Piezo transducers are output transducers which convert an electrical signal to

sound. Piezo transducers require a small current, usually less than 10mA, so

they can be connected directly to the outputs of most ICs. They are ideal for

buzzes and beeps, they may be connected either way

Loudspeaker

Loudspeakers are output transducers which convert an electrical signal to sound.

Usually they are called 'speakers'. Most circuits used to drive loudspeakers

produce an audio (AC) signal. Any DC will possibly damaging both the speaker and

the driving circuit. Loudspeakers may be connected either way round except in

stereo circuits when the + and - markings on their terminals must be observed to

ensure the two speakers are in phase.

Buzzer and Bleeper

These devices are output transducers converting electrical energy to sound. They

contain an internal oscillator to produce the sound which is set at about 400Hz

for buzzers and about 3kHz for bleepers. Buzzers and bleepers must be

connected the right way round, their red lead is positive (+).


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Inductor (coil)

An inductor is a coil of wire which may have a core of air, iron or ferrite (a brittle materialmade from iron). Its electrical property is called inductance and the unit for this is the

henry, symbol H. 1H is very large so mH and H are used:

1000H = 1mH and 1000mH = 1H.

Iron and ferrite cores increase the inductance. Inductors are mainly used in tuned circuits

and to block high frequency AC signals (they are sometimes called chokes). They pass DC

easily, but block AC signals. You can make your own inductor by winding a copper wire.

There is a very thin insulation for the wire, which is called Enamelled copper wire. This

allows the turns of the coil to be close together, but this makes it impossible to strip in the usual

way - the best method is to gently pull the ends of the wire through folded emery paper.

Integrated Circuits

ICs are usually shown as a rectangle with pins numbered in a

counterclockwise direction starting at the top left. To mark the

end containing pin 1, the plastic package sometimes shows a

half circle, a dot at pin 1, or a cut off corner. What appears on

the actual device depends upon the convention of the

manufacturer. Notice that each IC has a power connection

(marked Vcc or Vdd) and a ground connection GND (sometimes shown as Vss). For the devices

that we will use in Digital Lab, a DC power supply of between 5, from your IDL Digital Station.

The other pins on the ICs have various labels, which we shall learn describe the input and output

operation of the device. Be careful when removing ICs from the breadboard so as to not break

any of the pins. There is an IC puller on each bench (or you can use a screwdriver) to make this

easier.

Prototyping Your Design

Breadboard.

Temporary, no soldering is required and all the components can

be re-used afterwards. This is a way of making a temporary

circuit, for testing purposes or to try out an idea. It is easy to

change connections and replace components.

Stripboard

Permanent, soldered. Stripboard has parallel strips of

copper track on one side. The strips are 0.1" (2.54mm)

apart and there are holes every 0.1" (2.54mm).


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Printed Circuit Board

Permanent, soldered. Printed circuit boards have copper

tracks connecting the holes where the components areplaced. They are designed specially for each circuit and make

construction very easy.

HOW TO PLACE AND CONNECT COMPONENTS

Your circuit will be constructed using the IDL station where the components are placed on thebread board. The bread board has many strips of metal (usually made of copper) which run

underneath the board. The metal strips are laid out as shown from the Figure 9. These strips

connect the holes on the top of the board. This makes it easy to connect components together

to build circuits. To use the bread board, the legs of components are placed in the holes or

sockets. The holes are made so that they will hold the component in place. Each hole is

connected to one of the metal strips running underneath the board. Each wire forms a node. All

the wires that connect to the node will make up a net. A node is a point in a circuit where two

components are connected. Connections between different components are formed by putting

their legs in a common node. On the bread board, a node is the row of holes that are connected

by the strip of metal underneath.

Breadboard: a plastic block with sets of holes, spaced 0.100" apart, on both sides of a central

slot. The holes are arranged in groups of 5 , as in Figure 9, which are connected together

electrically with an internal metal clip into which wires are inserted. If two components are to

be connected in series, one side of each component would be inserted into the same metal

strip. The longer rows of holes (along the top and bottom in this photo and diagram there are

both horizontal and vertical sets on your breadboard) are connected together and are

commonly used for power and ground connections.


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Figure 9. Bread board and internal interconnection

On larger breadboards these longer lines may broken into portions (i.e. you need a jumper or

small length of wire between sections). ICs are installed to straddle the central slot between sets

of 5 holes (the horizontal trough in this photo and diagram); this allows for simple connection to

each of the pins of the IC. Be careful when inserting the ICs to be sure that all pins actually go

into the connectors (sometimes they bend underneath). Small resistors, LEDs, and other devices

can also be connected to the breadboard. Additional connections between components are

made using short lengths of wire. Note that we have a variety of colors of wire in the lab; try

using different colors for different types of connections (e.g. red for power, black for ground,

blue and yellow for signals).

The long top and bottom row of holes (X and Y rows) are usually used for power supply orground connections. The rest of the circuit is built by placing components and connecting them

together with jumper wires. Then when a path is formed by wires and components from the

positive supply node to the negative supply node, we can turn on the power and current flows

through the path and the circuit comes alive. For chips with many legs (ICs), place them in the

middle of the board so that half of the legs are on one side of the middle line and half are on the

other side.


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MAKING CONNECTIONS

Make sure that the power is OFF when you connect your components. You MUST have your

schematic with all pin assignment ready. You can start constructing the circuit by connecting allthe Power Supply and Ground to all ICs. In the case of digital lab, connect the input to the chips

then all the nets before connecting the output based on the schematic diagram. Connect one

level at a time. All the nets, pin to pin connection can be made by using the pin assignment that

you have in your schematic diagram. Once you have all connections are ready, switch ON the

power and start noting the output and change the input to fill up the truth table. In order for

you not to confuse yourselves, you can color-code the connection.

Figure 10. Components placement on a bread board.

If your circuit failed to give the necessary output, recheck your design. If you feel comfortable

with your design, you must be able to troubleshoot your circuit. The easiest way to troubleshoot

the circuit is by connecting a piece of wire to the output and check all the status of the node.

The node must indicate the intended logic level. This can be done by having a truth table that

has all the output for each function set. Test the circuit each set of the time. Once you identify

the faulty functional set, and then reconnect to construct the system.


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Digital Lab Procedures

For the digital lab, we will use the IDL Digital station to perform the experiments. Thus, you need

to familiarize with the digital station so that you know how and what to do in order to get theresults. Before you can start any experiment, make sure that these steps must be performed in

order to know the state of the digital station.

STEP1

Switch ON the power. Make sure that the LED turns RED. Else, make

sure that the board is properly connected. If, there is still no

indication that power is ON, notify your lab technician.

STEP 2

Test all your OUTPUT LED. All must be in working order. Connect

a wire from 5V to all the LED.

STEP 3

Test all your digital input switches. Connect a piece of wire from

each of the switch to one of the output LED. Look at the

indicator for Logic 1 and Logic 0. Make sure the entire switches

work.

STEP 4.

Test both of the pulser input. Keep in mind that the pulser is

able to give two types of pulse; active high and active low.

Active high will generate a pulse when you activate the switch.

Active low will constantly generate a Logic 1 until you press

the pulser that will generate an active low pulse. Connect a

piece of wire from the output LED to both pulser and test both

conditions.


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STEP 5

Two of the Seven Segments Display (SSD) must be tested by

connecting the multiplexed input of the SSD to the inputswitch. Each of the elements in the SSD must be switched on

using the DIP switch. Make sure that the entire DIP switch is

turned on. One can select the SSD by connecting the Common

Cathode (CC) of the SSD to ground. You have to make sure that

both SSDs are in good condition.

Analog Lab Procedures

You have to familiarize with the equipment that you want to use or may use prior to any labexperiment. As the IDL digital station is available in the lab, it is easier to construct all your

experiments on it as it is equipped with the bread board, power supply, basic function generator

and multimeter. Below are the steps that are recommended for you to follow. Failure to follow

the steps might lead to unsuccessful lab experiment or you might spend more time in

troubleshooting the experiments.

Step 1

It is very important for you to measure all your passive

components. You can use your multimeter to measure resistor

value or use LCR meter to measure other passive components.

In your calculation, you MUST use the actual value, not the

value indicated from the color or number from the component.

Failure to this will produce wrong calculation, since your actual

response is due to the actual value of the component.

Step 2

Prepare all your components. Note the actual value. Put them on a

piece of paper for a good lab practice. This will benefit you when you

do your calculation and your experiment.

Step 3

Once you all set with the component measurement and

setting, set your voltage supply for your experiment.

Measure the actual voltage from the voltage regulator, if

you are using the +5V or -5V supply. When the voltage from

the variable supply is set, switch off the IDL digital station.


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The voltage regulator might be out of order and it will destroy the electronic components, or

will give you wrong answer.

Step 4

While the power is off, populate your entire electronic

component. Connect all the power supply and ground for each

active component. It is advisable for you to have a sketch of

component placement on the protoboard.

Step 5Once you have laid out all the major or

active component on the breadboard,

followed by placing the passive

component. Then, connect all ground

connection before connecting the power

supply. Make sure that your IDL station is

switched off. One of the ways

to reduce error in the

connection is by measuring all

DC bias. If the DC bias voltage

that you measure is close

compared to your simulation

value, it means that your

connection is acceptable.

Step 6

You need to make sure that the oscilloscope is in good working order whenever you need to useit. Most of the scope that we have in the lab is self-calibrated. However, you have to do a probe

calibration prior to perform the experiment. Switch on the oscilloscope and connect the probe

to the internal source, then press the auto-set button. By hitting the auto set button, this will

automatically set the trigger, voltage amplification and time base. Observe the wave shown in

the screen. The time-base must be 1mS to indicate 1KHz. If the wave shown is not 1KHz, please

let the lab assistant to replace the oscilloscope. If you cannot see anything on the screen, your

probe may be faulty. Please make sure that you push the auto-set button before putting the

probe in the faulty component bin.


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If the square wave shown is not a square wave, you have to calibrate the probe. By using

provided tool or a screw driver, change the calibration capacitor of the probe until you can get a

nice square wave.

Overdamp Underdamp Compensated probe

Step 7

If you need to use a frequency generator, set the

frequency by using the dial then connect the output to

an oscilloscope.


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Step 8

Once you connect both probes, make sure that

you can see a nice wave on the screen. Adjust thefrequency and the amplitude accordingly based on

the measurement from the scope. If you cannot

see what you are suppose to have on the screen,

the probe that you use from the function

generator is a faulty probe. Put the faulty probe in

the faulty component bin that is available in the

lab

Step 9Make sure your IDL station and your function

generator are switched off before continuing

with your experiment.

Once you are sure with your setting, connect the

input from function generator to the input of

your circuit. You can have both channel from

your oscilloscope to be connected to the input

and output of the circuit. You only need one

ground connection from the scope, which is

from your input.

Sometimes it is a bit handy to use the function generator from the IDL station. Make sure that

you conduct steps above.

lab instruction

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