671 tech training electronics english

8/3/2019 671 Tech Training Electronics English

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The Braun Corporation 631 West 11th street P.O. Box 310

TECHNICA

ELECT


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INTRODUCTION

Electron flow

The Atom

Induction

Electric circuit

Resistance

Static electricity

The conductor

Ohms law

Cable nomogram

Kirchhoffs laws

Circuits

Joules

Measuri

Multime

TRMS

Meter re

Circuit c

Relay

Fuse

Circuit b


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WHY LEARNING ELECTR

To be more confidenTo be more confiden

approaching electricapproaching electric

To improve diagnosiTo improve diagnosi

To get it right the firTo get it right the fir

To improve CustomTo improve Custome

Why le

electro


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ELECTRON FLOW

When electrons flow from one atom to the

an organised matter, electric current flow e

Simply stated Electron flow = electricity.

Electricity is not something that must be gaconstructed . It is everywhere and in all thi

the attracting or repelling force that must bgathered.

This force is called Electro-motive For


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THE ATOMIs the basic unit of matter.

The smallest particle that we can find in a chemical sub

atoms, and by combining them to different molecules w

When a substance consists of one or more equal atoms i

The atom consists of a central, positively charged core,

electrons that are found in orbits around the nucleus. Pro

Nucleus of the Atom. For a neutral atom, the number of

have a positive charge. Neutrons have no charge. Electr

Ordinary electric current is the flow of electrons through

constituents of matter. An atom consists of a small, denelectrons that whirl about it in orbits, forming a cloud o

electrons to balance the positive charge of the nucleus, a

an atom determine its chemical and electrical propertie


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THE ATOMElectrons in each shell has a defined energy. Th

the electron is distanced to the nucleus, the highenergy in that electron shell.

Electrons in the outer shell are not strongly bon

the nucleus, and the atom may give up these ele

Because metals have few outermost electrons an

give them up easily, they are good conductors o

electricity or heat.

In substances like metals, electrons in the outer

basically moving freely. Connecting an electric

the metal exposes the charge carriers (electrons)

force, causing the electrons to relocate accordin

polarity.

In a conductor, the electrons will move towards the pos

This movement of electrons is called electric current.


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THE ATOMElectric current is defined by electrons moving

material.

Conductor

Electric conductors are materials where the elec

move between different atoms. Good conductors of elements containing less than 4 electrons in their outer rings.

Semi conductors

In a semiconductor there is a limited movement

electrons, depending upon the crystal structure omaterial used. The substances first used for sem

were the elements germanium, silicon, and gray

There are few free electrons compared to condu

Insulators (dielectric)

Is a substance that does not readily conduct hea

electricity. The electrons are bound and cannot

between the atoms.

Glass, porcelain and plastics are commonly used


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INDUCTIONElectromagnetic induction. is the production

of an electromotive force (emf) in a conductoras a result of a changing magnetic field about

the conductor.

Variation in the field around a conductor may

be produced by relative motion between the

conductor and the source of the magnetic

field, as in an electric generator, or by varying

the strength of the entire field, so that the field

around the conductor is also changing. Since

a magnetic field is produced around a current-

carrying conductor, such a field can be

changed by changing the current.

On figure A and C, the magnet is standing

still, the induced voltage (and current) is

equal to zero.


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INDUCTIONBy changing the magnetic field about the

conductor, there will be produced an

electromotive force (emf) in the conductor

The direction on the voltage (and current) idepending on if the magnetic field is

increasing or decreasing.

The level on the induced voltage is dependon how fast the magnetic field is changing.

The level on the induced voltage is dependon how strong the magnetic field is.

The direction on the induced voltage isdepending on the direction of the magnetic

field, (in case it is the north/south pole that

closest to the coil.


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INDUCTION

1 cycle


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ALTERNATOR

Cycle


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THE ELECTRIC CIRCUIT

The battery

Generates a direct current (DC) by a chemical p

current is in one direction only, and the battery

therefore be marked with (+) and (-).

The alternator

By revolving the coil in a magnetic field, an alte

(AC) is being induced. The polarity will alterna

The technical direction of current is from plus t

If the direction of current is defined in a el. sche

direction will be in force.

The actual direction of current, (electron current flow)

hand from minus to plus.

The electrons move from a negative charged area to a p

area.

A simple electric circuit consists of one power s

Example of power sources are:


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RESISTANCEResistance

-property of an electric conductor by which it

opposes a flow of electricity and dissipates elec

energy away from the circuit, usually as heat.

Optimum resistance is provided by a conductor

is long, small in cross section, and of a material

conducts poorly.

There is always a certain resistance in a conduct

There will always be a power loss due to a voltadrop during net movement or flow of electric ch

from one point to another or across some bound

The voltage drop will increase the greater the linresistance is. Usually we are aiming at a low lin

resistance by choosing the appropriate cable siz

material.


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STATIC ELECTRICITY-CH

Positive and negative charges behave in interesting ways. Two things w

charges (a positive and a negative) will attract, or pull towards each oth

charge (two positives or two negatives) will push away from each other

A charged object will also attract something that is neutral. Think abou

balloon stick to the wall. If you charge a balloon by rubbing it on your

electrons and has a negative charge. Holding it near a neutral object wi

object move. If it is a conductor, many electrons move easily to the oth

balloon as possible. If it is an insulator, the electrons in the atoms and mvery slightly to one side, away from the balloon. In either case, there ar

closer to the negative balloon. The balloon sticks. (At least until the ele

leak off.) It works the same way for neutral and positively charged obje

As you walk across a carpet, electrons move from the rug to you. Now

Touch a door knob and ZAP! The door knob is a conductor. The electro

knob. You get a shock.

We usually only notice static electricity in the winter when the air is ve

the air is more humid. The water in the air helps electrons move off you

not build up as big a charge.

As you walk across a carpet, electrons move from the rug to you. Now

Touch a door knob and ZAP! The door knob is a conductor. The electroknob. You get a shock.

We usually only notice static electricity in the winter when the air is ve

the air is more humid. The water in the air helps electrons move off you

not build up as big a charge. OBS! Things with the same charge repel e

get as far from each other as possible.

Static electricity is the imbalance of positive and negative charges.


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STATIC ELECTRICITY-ES

Electronic components are susceptible to damage from Electro

Discharge (ESD), when an ESD event occurs across their termfields. Electrostatic Discharge Susceptibility (ESDS) parts c

electrical and ground connections. Components found to be

resistors, resistor chips, discrete semiconductors, other thick- a

common ESDS component types and their relative sensitivitie

ESDS parts are usually as sensitive as the most sensitive ESDS

Device Type Range of Susceptibility (Volts)

VMOS 30 to 1800

MOSFET 100 to 200

GaAsFET 100 to 300

EPROM 100 +JFET 140 to 7000

SAW 150 to 500

OP AMP 190 to 5000

CMOS 250 to 3000

Schottky Diodes 300 to 2500

Film Resistors (Thick, Thin) 300 to 3000

Bipolar Transistors 380 to 7800

ECL (PDC Board Level) 500 to 1500

SCR 680 to 1000

Schottky TTL 100 to 2500

STATIC ELECTRICITY ES


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STATIC ELECTRICITY-ESElectrostatic Discharge (ESD)

Electrostatic discharge is a single, fast, high current transfer of electrost

Direct contact transfer between two objects at different potentials, or a h

between two objects when they are in close proximity. The prime sourc

mostly insulators and are typically synthetic materials, e.g., vinyl or pla

shoes, finished wood chairs, Scotch tape, bubble pack, soldering irons w

Voltage levels generated by these sources can be extremely high since t

distributed over their surfaces or conducted to other objects. The genera

caused by rubbing (or squeezing) two substances together is called the tExamples of sources of triboelectric electrostatic charge generation in a

environment include:

Walking across a carpet 1000 V1500

Walking across a vinyl floor 150 V250 V

Handling material protected by clear plastic covers 400 V600 V

Handling polyethylene bags 1000 V1200

Pouring polyurethane foam into a box 1200 V150

ICs sliding down an open antistatic shipping tube 25 V250 V

Note: For low RH (1

What can be done?

Treat floors with static dissipative treatments (benefit of this will pr

while.)

Raise air humidity to 40-50% rh with a humidifier

Use an antistatic wrist strap, which connects to your AC ground.Use different Shoes and clothing


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THE CONDUCTOR


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THE CONDUCTOR

Materials which have loosely held electrons are

Which variable makes an influence on the cable resistan

Length of the conductor. The longer, the greater the re

travel further and this takes more energy so the resistanc

is greater.

The cross sectional area. A large cross section will hathrough it at the same time.

Material specification. Silver,Copper,Gold and Alumi

because they have less than 4 electrons in their outer rin

Temperature. The temperature effects different materi

Other: (Number of strands, cooling effect, insulation

Resistivity ( ), is the material specific resistance. The

L = conductor length (m)

A = cross-sectional area for the conductor (m2 ) = Resistivity (m) Find the factor from a table

R = Resistance ()

R = x L/A AcabletwinondropVoltage

=

2:

OHMS LAW


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Ohms law is stating that the electric current i

flowing through a given resistance r

is equal to the applied voltage e

divided by the resistance, or i=e/r.

Ohms is the unit of resistance or how hard a

conductor resists the flow of electrical current.

For any circuit the electric current

is directly proportional to the voltage,

and is inversely proportional to the resistance.

OHMS LAW

U = R x I

R = U / I

I = U / R

U = Voltage, measured in Volt (V)

R = Resistance measured in ohm ()

I = Current, measured in Ampere (A)

OHMS LAW


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OHMS LAW

CABLE NOMOGRAM


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CABLE NOMOGRAM

KIRCHHOFFS LAW


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KIRCHHOFF S LAWKirchhoff's laws [for Gustav R. Kirchhoff], pa

of laws stating general restrictions on the curren

and voltage in an electric circuit.

The first of these states that at any junction of

paths, or node, in a network the sum of the

currents arriving at any instant is equal to the

sum of the currents flowing away.

[ I= 0 ]

[ I1 + I2 + + In = 0]

The second states that at any given instant the

sum of the voltages, (electromotive forces)

around any closed path, or loop, in the network

zero.[ E + U = 0]

[U = U1 + U2 + + Un]

E = e l ect r om ot i ve fo r ce , (emf), difference in electric potential, or volt

from which no current is being drawn. When current is drawn, the poten

SERIES CIRCUIT


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SERIES CIRCUIT

In a closed loop, the sum

of all voltage drops isequal to the supplied

voltage.

The current is the same in

each component

throughout the circuit.

When two circuit elements

are connected in series,

their effective resistance is

equal to the sum of theseparate resistances.

(U1 + U

I = I1 = I2

Reff. = R1

SERIES CIRCUIT VOLTAGE


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SERIES CIRCUIT VOLTAGE

Voltage drop is a condition that occurs in all cir

flows through a resistance producing work. Whpath, the supply voltage divides itself across the

PARALLEL CIRCUIT


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PARALLEL CIRCUIT

The elements of a parallel

circuit are connected so thateach component has the

same voltage across its

terminals.

The current flow is divided

among its parts, and the

total current is equal to the

sum of the currents in the

individual branches.

The total resistance is less

than that of the element

having the least resistance.

U = U1 = U

(I1 + I2 +

=

1

T

R

Ex. Find the total resistance for

the circuit. R1=100 and R2=200

1T R

1

R

1=

PARALLEL CIRCUIT


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PARALLEL CIRCUIT

A Parallel circuit has more than one path

for current to flow through. The loads maybe side by side and operate independent of

each other but are connected to the same

power source. In this way each component

can have a different current flow through it

while operating at full source voltage.

JOULES LAW


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JOULE S LAW

The relation between effect (power), current an

the formula P = U x I.Watt [for James Watt], (W),

Unit of power, or work done per unit time, equ

measure of electrical and mechanical power.

One watt is the amount of power that is deliver

a current of 1 ampere flows through the compo

P = power, measured in Watt (W)

U = Voltage, measured in Volt (V)R = Resistance measured in ohm ()

I = Current, measured in Ampere (A)

Q = Electric charge in Coulumb (C)

t = Time (s)

P = U x I

JOULES LAW


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JOULE S LAW

MEASURING


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MEASURINGVoltmeter

Measuring the voltage in a circuit, we use a volt

Always clamp your test pins parallel to the com

wish to measure. The measurement can be made

on the circuit without affecting the voltage level

that you have a multimeter with good quality).

Ammeter (Amp meter)

To measure the current in a circuit, we use a Am

Always clamp your test pins in series to the com

you wish to measure. (Except an clip-on ammet

Ohm meter

Instrument used to measure the electrical resista

conductor. It is usually included in a single packvoltmeter, and often an ammeter. Always clamp

pins in series to the components you wish to me

Whenever testing resistance, the circuit must be

voltage!

MULTIMETER


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MULTIMETERMost modern multimeters are digital and traditional an

Here is how a typical measurement are made in typical digital mu

DC voltage: The A/D circuitry in the multimeter is designed to

For higher voltages the input voltage is divided by a voltage di

amplifier.

AC voltage: Basically same idea as the DC measurement, exce

DC current: Input current is run through a known low ohm resiThis voltage is fed to the DC voltage measurement circuitry.

AC current: This is measures in the same way as DC current, e

electronics.

Diode test: A low current (typically less than 1 mA) is fed to th

voltage between measurement leads is measurement with DC v

Resistance measurement: An accurately known low current (va

The voltage (directly proportional to the resistance connected)

Some multimeters can have some of the following functionalities

Continuity tester: Works like the resistance measurement, if th

value (usually 50 to 300 ohms) it would make the beeper to sig Frequency: Input signal is converted to square wave first. The

gives output in Hz) or frequency to voltage converter.

Capacitance: Feed known frequency low amplitude signal thro

the capacitor. Other option is to measure the capacitor charge a

Temperature: Voltage from thermocouple sensor is amplified a

electronics.

METER RESISTANCE


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All meters have resistance.

The value of this resistance depends upon the voltagerange selected.A typical moving coil meter has aSENSITIVITY of 20,000 ohms per volt.This meansthat when the 1 volt range is selected the meter hasa resistance of 20,000 ohms.When the 10 volt rangeis selected it has a resistance of 200,000 ohms andso on.When the meter is connected to a circuit tomeasure voltage, this resistance will affect the circuitand therefore the accuracy of the measurement obtained.In Fig.1 the voltage across each resistor can be calculated. (However, it can be shown that since the resistors are of the s

them, and the voltage across each will be 15 volts.

Now if wevoltage, its resistance will be 20 x 20,000 = 400,000 ohms = If we connect it across the top resistor, as in Fig.2 then we hthis gives us 200,000 ohms and the circuit looks like Fig.3 Thresistor and 20 volts across the lower resistor.The meter wilvolts.Similarly, connecting the meter across the lower resisto

10v = 20 volts across the two resistors, when in fact there is meter on the highest range possible.This means that its resi

Digital meter have a very high resistance, typicallobtained are more accurate than those obtained u

meter look for a sensitivity greater than 20,000 oh

THE EFFECT OF METER RESISTANCE

TRMS


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True RMS (True Root Mean Square) = True effect

Definition of TRMS:In a circuit whose impedance consists of a pure resistan

the rms value of an AC wave is often called the effectiv

value. For example, if an AC source of 100 volts rms is

connected across a resistor, and the resulting current

causes 50 watts of heat to be dissipated by the resistor,

then 50 watts of heat will also be dissipated if a 100-vo

DC source is connected to the resistor.

Remember that an average responding multimeter willexhibit substantial errors when measuring other wave

forms as sine waves, as shown below.

CIRCUIT CONDITIONS


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There are a number of terms used to describe va

and some refer to specific circuit faults.These terms are:

Closed circuitOpen circuitShorted circuitShort to ground

1. Closed Circuit

When the circuit provides a continuous path fro

back to the power source, it is called a closed ci

CIRCUIT CONDITIONS


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2. Open Circuit

If a circuit is broken by any means, such as opean open circuit and current will cease to flow. T

since they need to be switched OFF at various

such as when a wire is damaged or a switch fai

CIRCUIT CONDITIONS


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3. Shorted (Short) Circuit

A short circuit means that the original circuit ha

An example of this would be when the insulatio

causing the windings to touch together or beco

normal current flow, resulting in an increase in

effectiveness and life of that coil.(A fuse may al

CIRCUIT CONDITIONS


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4. Short to Ground

A short to ground occurs when a wire or termin

Movement wearing away insulation or a wire be

component can cause this. A short circuit will c

blow.

RELAYS


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A relay is a switching device operated by a low

and closing of another circuit of higher current c

consuming component to operate with minimal

high current carrying circuit to a minimum.

Applying voltage to the relay coil causes a elect

changes the contacts from their normal position

Relays may be divided into four types

1.Normally open

2.Normally closed

3.Transfer types

4.Mixed types

RELAYS


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1. A normally open (N.O) relay will not allow

2. The contacts of a normally closed (N.C) re

high current to flow through the contacts.

3. A transfer relay has two operational states,

to another when its windings are not energi

circuit when energised. In the relay schema

are switched OFF. Current will flow from t

terminal # 4.

4. A mixed relay is used to open and close tw

SW 1 Battery

Flow

Flow

Mixed typ

FUSE


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A fuse is generally inserted into an electrical ci

power source which includes the wire that conn

device, or to protect the electronic equipment. T

specify a fuse rated to open the electrical circui

open the circuit if the electronic device fails in

excessive current when they fail). If a fuse larg

mistake when installing the equipment may cau

WHEN, not if, WHEN you're thinking of repla

ask yourself if you know more than the enginee

a hurry when installing electronic equipment. T

cents for a fuse is better than $50 labour plus thjob.

Fuse Opening Time

A fuse does not blow when the current reachesrated current without opening. A fuse will take

conditions. A fuse will pass significantly more

may take 10 minutes or more to blow a fuse at

CIRCUIT BREAKER / FUSE


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A circuit breaker's function is, like a fuse, to break a circ

predetermined amount of current is passed. The picture

version of a self-resetting circuit breaker. In this device, from the battery terminal, through the bi-metal strip and

terminal. The bi-metal strip is made of two different typ

have different coefficients of expansion. This means tha

more than the other when the rise in temperature is the s

In this case, the two metals are bonded to each other. (N

that this is a simplified diagram). When the strip heats u

flow through it, one type of metal expands more than the

the black metal expands more than the red and the strip t

upward and disconnect the contacts. You can see that th

bend as the current increases. When the temperature reac

the piece will snap into the open position and the curren

bi-metal strip is stamped into a special shape, which cau

This will assure that there is EITHER a solid connection

disconnect. You can see a similar snap action in the top If you push down on the top it starts to bend downward.

reaches a certain point, the top will snap down. If you re

slowly, the top will snap into its original position. This i

when the bi-metal strip cools in the breaker.

RESISTOR


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The resistance value can be printed on the comp

with different colour rings around the resistance

The value is given by for rings. The first two rin

The third ring states the number of zeros that h

The fourth ring states the tolerance value, from

Band 1 Band 2 Band 3 Band 4 Band 5 Band 6

Color 1st Digit2nd Digit3rd Digit Multiplier ToleranceReliability

Black 0 0 1

Brown 1 1 1 10 1% 1%

Red 2 2 2 100 2% 0.10%

Orange 3 3 3 1,000 3% 0.01%

Yellow 4 4 4 10,000 0.00%

Green 5 5 5 100,000

Blue 6 6 6 1,000,000

Violet 7 7 7 10,000,000

Gray 8 8 8 100,000,000

White 9 9 9 1,000,000,000

Gold x 0.1 5%

Precision Resistor Color Codes

Read the resistance value by means

of the colour codes.

Verify the value with an ohmmeter.Co

Bla

Bro

Re

Ora

Yel

Gre

Bl

Vio

Gr

Wh

Go

INDUCTIVE SWITCH


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Proximity Switches allow the user to detect

the presence of material without having to

make physical contact. Inductive sensors are

used when the target is metal. These are the

most widely used switches in industry today.

Proximity switches are available in either

Shielded or Unshielded versions. Shielded

versions will detect metal only at the sensing

face. Unshielded versions usually have a

larger sensing range, but the drawback is that

they will detect metal around the sensinghead. This means that the surrounding area

(normally 3 times the switch diameter, and

twice as deep as the sensing range) must be

free from metal objects.An inductive proximity switch consists of 4 main components: coil, osc

DC switches, thyristor in AC switches). The oscillator creates a high fre

target enters that field, eddy currents are induced in the metal target (he

maintain the eddy currents in the target. As the target enters the sensing

oscillator, and it stops. The detection circuit senses this and signals the

range, the oscillator resumes functioning, and the switch returns to its n

DIODE


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The Diode is a two-terminal electronic device th

only one direction.

A diode has a low resistance to electric current i

the reverse direction. This property makes a dio

alternating current (AC) into direct current (DC

direction exceeds a certain value, a semiconduc

heavily in the direction of normally high resista

breakdown occurs remains nearly constant for a

called avalanching. A diode using this property

regulate the voltage in a circuit. (See Zener diod

When voltage is applied to a diode and current i

flowing through the diode, there will be approxi

a 0.6 volt drop across the diode.

Rectifier

LED


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A light-emitting diode (LED) produces light as

act as the light source of lasers. The emitted col

commonly available colours are red, green, amb

yellow and amber have a working voltage of ap

data sheet for each LED to find the exact value.

by the breakdown voltage of the particular semi

When using an LED in a circuit, the exact working

voltage is not extremely important. The most

important thing is the current flow through the

LED. A series resistor must limit the current

through the diode. An LED has a specifiedmaximum continuous current rating. Most LEDs

can pass 20 milliamps continuously without

damage but it is not necessary to use the maximum

rated current. An LED will light with much less

current. The difference between high current andlow current will be the brightness of the LED. To

decide what resistor value is needed, you subtract

the working (forward) voltage from the power

supply voltage and divide that number by the

desired current flow.

ZENER DIODE 1


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Zener diodes are generally used for voltage regu

The diodes are used with reverse polarity when

compared to their rectifier counterparts (you ho

them up backwards to make them work properly

All diodes have a point at which they will condu

current when sufficient reverse voltage is applie

Most diodes are damaged when the reverse volt

reaches the breakdown (or avalanche) voltage.

diode circuits have a current limiting resistor in

with the diode as part of their design. The other

of the resistor is connected to the cathode of theThe other end of the zener, the anode, is connec

zener, the voltage on the cathode of the zener w

going to be close the rated zener voltage. You c

rated zener voltage by varying the value of the rthrough the diode.

Sym

ZENER DIODE 2


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If you look at the curve,

you can see that a

change in current (near

the breakdown voltage)

corresponds to a smallchange in the

breakdown voltage.

This type of circuit is

good for use as a

voltage reference but it

is not very good to

supply regulated

voltage to circuits that

draw a large amount ofcurrent.

CAPASITORA it i l t i d i hi h i t f


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A capacitor is an electronic device which consists of

by an insulator. The capacitor's value (its 'capacitance

plates and the distance between the plates (determinecommonly referred to in microfarads, one millionth o

farad is such a large amount of capacitance that it wo

capacitor works basically as a resistor that is dependi

The capacitor is used to store charge in an electrical cor remove unwanted electrical pulses in a circuit. A c

and discharges much more efficiently (batteries, thou

called electrolytic, meaning that their dielectric is ma

or tantalum foil conductor. A capacitor has a value o

charge with one volt across it.

These capacitors are often used to

stabilize a pulsating direct current. The

capacitors have a defined conducting

direction and are marked positive and/or

negative, (as a battery).

r

nl

A

U

QC

0

)1(

=

==

C = Capacitanc

Q = Electric cha

U = Voltage V

= Permittivity

0 = Permittivit

CAPASITORN l i d fi d it


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Non-polarized fixed capacitor

A non-polarized ("non polar") capacitor is a type of cap

connected either way in a circuit. Ceramic, mica and so

also sometimes hear people call them bipolar capacito

Polarized fixed capacitor

A polarized ("polar") capacitor is a type of capacitor thaone way in a circuit. The positive lead is shown on the s

"+" symbol. The negative lead is generally not shown o

capacitor with a bar or "-" symbol. Polarized capacitors

Note that you really need to pay attention to correctly h

to polarity, as well as not pushing a capacitor past its ra

hard enough, it is possible to begin "electrolyzing" the m

usually have a pressure relief vent to prevent catastroph

eyesight on this).

Termin

Unit table

1pF = 10-12F = 1/1000 000 000 000

1F = 10-6F = 1/1000 000

1mF = 10-3 F = 1/1000

TRANSISTOR

Th t i t ll h 3 t i l Th


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The transistor generally has 3 terminals. The co

terminal is called the base. The other 2 terminal

known as the emitter and the collector and they

virtually all of the current flowing through the tThere are 2 basic configurations of bipolar trans

one is an 'NPN' the other is a 'PNP'. The two are

similar. The biggest difference is the direction ocurrent flow through the collector and emitter.

On an NPN transistor, the base must have a pos

voltage with respect to the emitter.

By varying IB , we can control a large current thIK .The transistor uses a small current to control

larger current, a little like a relay.

The transistor function can also be looked on asdiodes connected together like on the picture to

right. A transistor needs to have a small amount

voltage difference between the base and the emi

The required voltage is usually about 0.6 volts.

TRANSISTOR

Th i t l l h th di ti f th


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The pictures clearly shows the directions of the

-

+

+

TRANSISTOR

The transistor is being used in many different el


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The transistor is being used in many different el

small current to control a larger current, a little l

the transistor, is that it works much faster comp

breaker contacts that can get burned. You can al

ON/OFF). Compared to the relay, the transistor

not as flexible regarding the size

of the control current in relationto the working current.

In order to use a weak signal,

for handling a high working

current, there are often beingused several transistors

connected to each other.

The NPN transistor to the right isused as a switch.

WORK TASKS


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WORK TAN

TEAMW

DEVIDE IN

2-3 PERSONS O

THE LEARNING PYRAMID


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Lectures

Reading

Audio visual (see/h

Demonstration

Discussion group

Learning by doing (pra

Teach others / Immediate use

BREAK

CORRECT PROC


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CORRECT PROC

RECTIFICATION OF EL

THEORY & PRACTICE


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Theory put into

practice

You will be

making practical

lab tasks,

makingelectrical

circuits

combined with

theoreticalcalculations on

different

circuits.

WORK TASKS -INSTRUM

If h l i h i


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If you connect the multimeter to the circu

to the picture on the right, what can be me

How do you hook up an ammeter in a circ

Which value does the instrument show?

If you connect a multimeter to this circuit

be measured?

How do you hook up the voltmeter in the shown to the right?

Which value does the instrument show?

WORK TASKS RESISTAN

Connect according to the figure. Measure t


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g g

Unscrew the bulb. What is the voltage over

What can we learn based on this experienc

WORK TASKS SERIES

Connect according to drawing A, use a 12V


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g g ,

voltage between 0 and 10V. What happens

Connect according to figure B, E = 10V. Hilluminating when using:

Why?

Connect according to figure C, U = 10V. H

illuminating now, and why?

What do we name this kind of circuit and wresistance.

47

WORK TASKS SERIES

Set the input voltage to exactly 12,00


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p g y

Measure and calculate every part voltage a

note in the table below.

Sum up all part voltages and note this on th

table.

U Measured U Calculated

UAD -----

UAB

UBC

UCD

Total: U AB + U BC + U CD =

WORK TASKS PARALLE

U = 10V R1 = 47 R2 = 100 R3 = 47


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Make the connection, and use only the 470does the lamp illuminate?

Add only the 100 resistance. How strong

now?

Now, add on the 47 resistance. How stronilluminating now?

Why?

What do we name this kind of circuit and wthe total resistance.

WORK TASKS PARALLESet input voltage to exact 16,00 V


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Measure and calculate each part current an

note in the table below.Sum up all part currents and note this on th

the table, IR1, IR2 and IR3 .

IMeasured ICalculated

UR

UR1

UR2

UR3

Total: IR1 + IR2 + IR3 =

WORK TASKS POWER

What is the heating effect for the total circu


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Which heating effect is produced by each p

What is the voltage supplied, when the 20 kapprox. 5 mW?

a) What is the resistance when it emits 9supplied 30V to the circuit?

b) Connect the resistance, calculated from

circuit, turn on the power. What happens to

WORK TASKS THERMIC RE


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Measure and fill in the missing values.

Calculate and fill in the resistance of the bu

and the three resistances.

A) Why is there a difference between themeasured and the calculated resistance?

B) Why is it important to understand thisphenomena, and can you come up with

practical examples for this.

WORK TASKS RELAY

Based on what you have learned about induction


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Explain why, on some relays that a diode iconnected in parallel to the relay coil.

Explain the process and what will happenwhen we turn the power on, (activate the

relay) and then off (deactivate the relay).

Connect the multimeter to 85 and 86. Set

the multimeter on Min/Max record, 1ms an

set the range to 4000V (1000V). Connect

and disconnect the power plug(set the powsupply to 12V). Read the Min/Max values

recorded. Explain your findings.

WORK TASKS TRANSIST

NPN transistor as a switch


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Given information:HFE = 100 Iload = 1 A

UKE = 0,5 V UB = 10 V

UBE = 0,5 V

Calculate and fill in the missing values.

URL = ?RL = ?

Ib = ?

RB = ?

PRL = ? (Load effect on RL)

HFE =IK

IB

WORK TASKS TRANSIST

NPN transistor as a regulator


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Estimate a serial resistance between baseand source to protect the transistor.

U source = 10V, Imax (load) = 0,2A

Connect a 12V/0,2A light bulb and use theNPN transistor to adjust/variate the light

intensity on the bulb.

U source = 10V

Use the multimeter and measure the

resistance when there is no illumination.

What is the Max/Min resistance?

WORK TASKS ZENER DI

Connect according to fig. 1 and set the powexactly 4 5V Verify that the buzzer gives a


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exactly 4,5V. Verify that the buzzer gives a

Turn off the power and connect according Set the power to exactly 4,5V. Does the bu

now?

Increase the voltage to 5,5V. Does the buzznow?

Explain the results and your findings from 3.

NOTES


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TRMS


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Course participant

Cut off here


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