Ep Lab Word Edited

P.S.R.ENGINEERING COLLEGE, SIVAKASI-626 140

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

YEAR: I

SEMESTER: I

ENGINEERING PRACTICES

LABORATORY

(12F1Z9)

LAB MANUAL

[Group B]

I

SHANMUGANATHAN ENGINEERING COLLEGE, ARASAMPATTI

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

Class/ Semester

Sub & Code

: I/ I

: EE6162 - Engineering Practices Laboratory [Group B]

LIST OF EXPERIMENTS

v STUDY OF SYMBOLS

v SIMPLE WIRING CONNECTION

v STAIRCASE WIRING

v FLUORESCENT LAMP WIRING

v MEASUREMENT OF POWER USING WATTMETER

v MEASUREMENT OF ENERGY USING SINGLE PHASE ENERGY METER

v STUDY OF MEASUREMENT OF RESISTANCE USING COLOR CODING

v MEASUREMENT OF AC SIGNAL PARAMETERS USING CRO

v STUDY OF BASIC LOGIC GATES

v HALF WAVE AND FULL WAVE RECTIFIER

v MEASUREMENT OF RESISTANCE TO EARTH OF ELECTRICAL

EQUIPMENT

I

Ex.No: STUDY OF SYMBOLS

Date:

AIM:

To study the various symbols used in electric circuits.

COMPONENT

WIRE CONNECTIONS

Wire

To pass current very easily from one part

of a circuit to another.

A 'blob' should be drawn where wires are

connected (joined), but it is sometimes

omitted. Wires connected at 'crossroads'

should be staggered slightly to form two T-

junctions, as shown on the right.

In complex diagrams it is often necessary

to draw wires crossing even though they

are not connected. I prefer the 'bridge'

symbol shown on the right because the

simple crossing on the left may be misread

as a join where you have forgotten to add a

'blob'!

CIRCUIT SYMBOL

DESCRIPTION

Wires joined

Wires not joined

POWER SUPPLIES

Supplies electrical energy.

The larger terminal (on the left) is positive

(+).

A single cell is often called a battery, but

strictly a battery is two or more cells joined

together.

Supplies electrical energy. A battery is

more than one cell. The larger terminal (on

the left) is positive (+). The smaller

terminal (on the right) is negative (-).


DC = Direct Current, always flowing in

one direction.


AC = Alternating Current, continually

changing direction.

A safety device which will 'blow' (melt) if

the current flowing through it exceeds a

specified value.

Cell

Battery

DC supply

AC supply

Fuse

1

Transformer

Two coils of wire linked by an iron core.

Transformers are used to step up (increase)

and step down (decrease) AC voltages.

Energy is transferred between the coils by

the magnetic field in the core. There is no

electrical connection between the coils.

A connection to earth. For many electronic

circuits this is the 0V (zero volts) of the

power supply, but for mains electricity and

some radio circuits it really means the

earth. It is also known as ground.

A transducer which converts electrical

energy to light. This symbol is used for a

lamp providing illumination, for example a

car headlamp or torch bulb.


energy to light. This symbol is used for a

lamp which is an indicator, for example a

warning light on a car dashboard.


energy to heat.


energy to kinetic energy (motion).


energy to sound.

Earth

(Ground)

OUTPUT DEVICES: LAMPS, HEATER, MOTOR, etc.

Lamp (lighting)

Lamp (indicator)

Heater

Motor

Bell

Buzzer


energy to sound.

A coil of wire which creates a magnetic

field when current passes through it. It may

have an iron core inside the coil. It can be

used as a transducer converting electrical

energy to mechanical energy by pulling on

something.

A push switch allows current to flow only

when the button is pressed. This is the

switch used to operate a doorbell.

2

Inductor

(Coil, Solenoid)

Switches

Push Switch

(push-to-make)

Push-to-Break

Switch

On-Off Switch

(SPSTS)

This type of push switch is normally closed

(on), it is open (off) only when the button

is pressed.

SPSTS = Single Pole Single Throw

Switch. An on-off switch allows current to

flow only when it is in the closed (on)

position.

SPDTS = Single Pole Double Throw

Switch. A 2-way changeover switch directs

the flow of current to one of two routes

according to its position. Some SPDT

switches have a central off position and are

described as 'on-off-on'.

DPST = Double Pole, Single Throw

Switch. A dual on-off switch which is

often used to switch mains electricity

because it can isolate both the live and

neutral connections.

DPDT = Double Pole, Double Throw

Switch. This switch can be wired up as a

reversing switch for a motor. Some DPDT

switches have a central off position.

An electrically operated switch, for

example a 9V battery circuit connected to

the coil can switch a 230V AC mains

circuit.

NO = Normally Open, COM = Common,

NC = Normally Closed.

2-way Switch

(SPDTS)

Dual On-Off

Switch

(DPSTS)

Reversing Switch

(DPDTS)

Relay

Resistors

Resistor

A resistor restricts the flow of current, for

example to limit the current passing

through an LED. A resistor is used with a

capacitorinatimingcircuit.

Some publications still use the old resistor

symbol:

This type of variable resistor with 2

contacts (a rheostat) is usually used to

control current. Examples include:

adjusting lamp brightness, adjusting motor

speed, and adjusting the rate of flow of

charge into a capacitor in a timing circuit.

3

Variable Resistor

(Rheostat)

Variable Resistor

(Potentiometer)

This type of variable resistor with 3

contacts (a potentiometer) is usually used

to control voltage. It can be used like this

as a transducer converting position (angle

of the control spindle) to an electrical

signal.

This type of variable resistor (a preset) is

operated with a small screwdriver or

similar tool. It is designed to be set when

the circuit is made and then left without

further adjustment. Presets are cheaper

than normal variable resistors so they are

often used in projects to reduce the cost.

A capacitor stores electric charge. A

capacitor is used with a resistor in a timing

circuit. It can also be used as a filter, to

block DC signals but pass AC signals.

A capacitor stores electric charge. This

type must be connected the correct way

round. A capacitor is used with a resistor in

a timing circuit. It can also be used as a

filter, to block DC signals but pass AC

signals.

A variable capacitor is used in a radio

tuner.

This type of variable capacitor (a trimmer)

is operated with a small screwdriver or

similar tool. It is designed to be set when

the circuit is made and then left without

further adjustment.

Variable Resistor

(Preset)

CAPACITORS

Capacitor

Capacitor

polarized

Variable Capacitor

Trimmer Capacitor

DIODES

Diode

LED

Light Emitting

Diode

Zener Diode

A device which only allows current to flow

in one direction.


energy to light.

A special diode which is used to maintain a

fixed voltage across its terminals.

4

Photodiode

TRANSISTORS

A light-sensitive diode.

Transistor NPN

A transistor amplifies current. It can be

used with other components to make an

amplifier or switching circuit.

Transistor PNP

A transistor amplifies current. It can be

used with other components to make an

amplifier or switching circuit.

Phototransistor

A light-sensitive transistor.

AUDIO AND RADIO DEVICES

Microphone

A transducer which converts sound to

electrical energy.


energy to sound.

Earphone

Loudspeaker


energy to sound.

Piezo Transducer


energy to sound.

An amplifier circuit with one input. Really

it is a block diagram symbol because it

represents a circuit rather than just one

component.

Amplifier

(general symbol)

5

Aerial

(Antenna)

A device which is designed to receive or

transmit radio signals. It is also known as

an antenna.

METERS AND OSCILLOSCOPE

Voltmeter

A voltmeter is used to measure voltage.

Voltmeter must be connected across the

terminal.

An ammeter is used to measure current. It

is always connected in series with the

circuit.

A galvanometer is a very sensitive meter

which is used to measure tiny currents,

usually 1mA or less.

An ohmmeter is used to measure

resistance. Most multimeters have an

ohmmeter setting.

An oscilloscope is used to display the

shape of electrical signals and it can be

used to measure their voltage and time

period.

A transducer which converts brightness

(light) to resistance (an electrical

property).

LDR = Light Dependent Resistor

A transducer which converts temperature

(heat) to resistance (an electrical property).

A NOT gate can only have one input. The

'o' on the output means 'not'. The output of

a NOT gate is the inverse (opposite) of its

input, so the output is true when the input

is false. A NOT gate is also called an

inverter.

An AND gate can have two or more inputs.

The output of an AND gate is true when all

its inputs are true.

Ammeter

Galvanometer

Ohmmeter

Oscilloscope

SENSORS (INPUT DEVICES)

LDR

Thermistor

LOGIC GATES

NOT

AND

6

NAND

A NAND gate can have two or more

inputs. The 'o' on the output means 'not'

showing that it is a Not AND gate. The

output of a NAND gate is true unless all its

inputs are true.

An OR gate can have two or more inputs.

The output of an OR gate is true when at

least one of its inputs is true.

A NOR gate can have two or more inputs.

The 'o' on the output means 'not' showing

that it is a Not OR gate. The output of a

NOR gate is true when none of its inputs

are true.

An EX-OR gate can only have two inputs.

The output of an EX-OR gate is true when

its inputs are different (one true, one false).

An EX-NOR gate can only have two

inputs. The 'o' on the output means 'not'

showing that it is a Not EX-OR gate. The

output of an EX-NOR gate is true when its

inputs are the same (both true or both

false).

OR

NOR

EX-OR

EX-NOR

RESULT:

Thus the various symbols in electric circuits were studied and drawn.

7

LAYOUT DIAGRAM:

8

SIMPLE WIRING CIRCUIT

CIRCUIT DIAGRAM:

Ex.No: SIMPLE WIRING CONNECTION

Date:

AIM:

To study and practice the various types of electrical wiring circuit

connections.

TOOLS REQUIRED:

S.No.

1.

2.

3.

4.

Tester

Electrician Knife

Wire Cutter

Screw Driver

TOOLS

QUANTITY (No.)

1

1

1

1

MATERIAL REQUIRED:

1. Single Pole One Way Switch

2. Lamps

3. Wires

4. Two Pins or Three Pins Wall Socket

5. Batten Holder

THEORY:

Any conductor which is composed of a conducting material, and is uniform

in diameter and circular in cross section is called wire. A length of single insulated

conductor or two or more such conductors each provided with its own insulation

which are laid up together is called a cable. A cable consists of the following three

main parts: a) Conductor, b) Insulation Covering and c) Protective covering.

-

-

-

-

-

3 No.s

3 No.s

Required

1 No.

3 No.s

9

10

MODEL CALCULATION:

CONDUCTOR:

Any pure metal which offers low resistance to the passage of electric current

is called a conductor. The current is taken from one place to the other by means of

a conductor. Copper is used as a conductor in majority of applications.

INSULATION CONVERING:

It is the covering which bounds the current flow in a definite path. The

insulation of the cable must be strong enough because a leakage current will start

giving electrical shocks and cause fire.

PROTECTIVE COVERING:

It protects the insulation covering against any mechanical injury.

VARIOUS TYPES OF WIRES:

The various types of wires are vulcanized Insulation Rubber(VIR) wires,

Cab Type Sheathed(CTS), Poly Vinyl Chloride (PVC) wires,flexible

Wires,etcout of these for house hold applicatios PVC wires are used.

PRECAUTIONS:

v The circuit should be checked by series test lamp.

v Bare portion of the conductor should not come out of the terminal and the

insulation of the conductor should keep up to the end of the terminal.

v All the connections should be tight.

v All the switches should be connected in positive wire.

v Always keep the live wires on the right hand side.

PROCEDURE:

v First the layout diagram of the electrical circuit is made.

v The circuit is made with the given material.

v The output is verified by switching ON the switches.

RESULT:

Thus the various electrical circuit connections were made and studied.

11

STAIRCASE WIRING

CIRCUIT DIAGRAM:

12

Ex.No: STAIRCASE WIRING

Date:

AIM:

To construct and control the status of lamp using two way switch by Stair

Case wiring.

APPARATUS REQUIRED:

S.No.

1.

2.

3.

4.

5.

Tester

Electrician Knife

Wire Cutter

Screw Driver

Combination Plier

APPARATUS

QUANTITY

1

1

1

1

1

MATERIAL REQUIRED:

1. Two Way Switches

2. Lamp

3. Wires

4. Lamp Holder

PRECAUTIONS:

v The circuit should be checked by series test lamp.

v Bare portion of the conductor should not come out of the terminal and the

insulation of the conductor should keep up to the end of the terminal.


v All the switches should be connected in positive wire.


13

-

-

-

-

2 No.s

1 No

Required

1 No

LAYOUT DIAGRAM:

TABLULATION:

Sl.NO

1

2

3

4

Switch A

1

Switch B

2

Output-Lamp

OFF

14

PROCEDURE:


v The connections are made as per the wiring diagram.

v The output table is verified by switching ON the switches.

RESULT:

Thus the stair case wiring was constructed and output was verified.

15

FLUORESCENT TUBE WIRING

CIRCUIT DIAGRAM:

16

Ex.No: FLUORESCENT LAMP WIRING

Date:

AIM:

To construct and study the working of a fluorescent lamp circuit.

APPARATUS REQUIRED:

S.No.

1.

2.

3.

4.

5.

Tester

Electrician Knife

Wire Cutter

Screw Driver

Combination Plier

TOOLS

QUANTITY (No.)

1

1

1

1

1

MATERIAL REQUIRED:

1. Choke

2. Starter

3. Tube light holder, frame

4. Tube light

5. Connecting wires

PRECAUTIONS:


v Twisting of wires should be avoided.


THEORY:

The fluorescent tubes are usually available in lengths of 0.61 m and 1.22 m.

The various parts of fluorescent tube include.

-

-

-

-

-

1 No.

1 No.

1 No.

1 No.

Required

17

18

MODEL CALCULATION:1. Glass tube

2. Starter

3. Choke

4. Fluorescent materials

5. Filaments

The inside surface of the fluorescent tube is coated with a thin layer of fluorescent

material in the form of powder. The tube also contains low pressure argon gas and

one or two drops of mercury. The two filaments are coated with electron emissive

material. The starter (initially in closed position) puts the filaments directly across

the supply mains at the time of starting, there by initiating emission of electrons.

After 1 or 2 seconds the starter switch gets opened. The interruption of current

makes the choke to act like ballast providing a voltage impulse across the

filaments. Due to this, ionization of argon takes place. Mercury vapour arc

provides a conducting path between the filaments. The starter used may be of

thermal starter or glow starter whose function is to complete the circuit initially for

preheating the filaments (to initiate emission of electrons) and then to open the

circuit for high voltage across choke for initiating ionization.

PROCEDURE:


v The connections are made as per the wiring diagram.

v The output is verified.

RESULT:

Thus the fluorescent lamp circuit connection was given and studied.

19

CIRCUIT DIAGRAM:

(0 10A) MI

P

10 A

300V, 10A, UPF

M

V

L

A

C

230 V, 1

50 Hz, A.C.

D

P

S

T

S

10 A

1 Variac

(0 270V)

V

(0 300V) MI

L

O

A

D

N

TABULATION:

Multiplication Factor = .

S.No.

Voltage

(Volts)

Current

(Ampere)

Wattmeter Reading (Watts)

Observed value

Actual value

20

MEASUREMENT OF POWER USING WATTCIRCUIT

Ex.No: MEASUREMENT OF POWER USING WATTMETER

Date:

AIM:

To measure the Power consumed by a Single Phase Resistive Load by using

Wattmeter.

APPARATUS REQUIRED:

S.No.

1.

2.

3.

4.

5.

APPARATUS

Ammeter

Voltmeter

Wattmeter

Single Phase Resistive Load

Connecting Wires

TYPE / RANGE

(0 10A) MI

(0 300V) MI

300V, 10A, UPF

QUANTITY

1

1

1

1

Required

FORMULA USED:

v Multiplication Factor = Current Coil Rating x Voltage Coil Rating x Power Factor

Full Scale Reading of Wattmeter

v Actual Power in Watts = Observed Reading x Multiplication Factor

THEORY:

A wattmeter is an instrument specially designed to measure average power

consumed by a load. It has two coils:A current coil that measures the current and a

voltage coil that measures the voltage. The wattmeter takes into account the phase

shift, if there is any between the current sensed by its current coil and the voltage

sensed by its voltage coil. If the voltage drop across as measured the voltage coil is

Vm cos(t + ) A, then the average power P measured by the wattmeter in watts is

Vm Im Cos ,where = is the power factor angle. The voltage coil of the

wattmeter, its reading will be 0.707 Vm.

21

22

PRECAUTIONS:

v Single phase variac should be kept at minimum position, during starting

period.

v No load should be connected when the DPSTS is closed or opened.

PROCEDURE:

v The connections are made as per the circuit diagram.

v Rated Voltage is set in the voltmeter, by gradually varying the single phase

variac.

v Resistive load is switch ON.

v Load is gradually increased and the ammeter, voltmeter & wattmeter

readings are noted.

RESULT:

Thus the power consumed by a single phase resistive load was measured.

23

CIRCUIT DIAGRAM:

(0 10A) MI

P

10 A

Energy Meter

S1

C1

C2

L1

A

230 V, 1

50 Hz, A.C.

D

P

S

T

S

10 A

1 Variac

(0 270V)

V

P1

(0 300V) MI

P2

L

O

A

D

N

S2

L2

TABULATION:

Energy Meter Constant =

Sl.

No.

Voltage

(Volts)

Current

Power

Time

Number of

Actual

True

%

Error

(Ampere) (Watts) (Seconds) Revolutions

Energy Energy

(KWh)

(KWh)

24

MEASUREMENT OF ENERGY USING SINGLE PHASE ENERGY METER

AIM:

To measure the Energy consumed by a Single Phase Resistive Load by using

Single Phase Energy Meter.

REFERENCE:

1.Engineering Practices Laboratory by V. Ramesh Babu VRB Publishers.

2.Engineering Practice by M.S. Kumar D D Publications.

APPARATUS REQUIRED:

S.No.

1.

2.

3.

4.

5.

6.

APPARATUS

Ammeter

Voltmeter

Single Phase Energy Meter

Stop Watch

Single Phase Resistive Load

Connecting Wires

Analog

3 KW, 230 V

TYPE / RANGE

(0 10A) MI

(0 300V) MI

QUANTITY

1

1

1

1

1

Required

FORMULA USED:

v Actual Energy in KWh = Power in Watts x Time Taken in Seconds

1000 x 3600

v Power in Watts = Voltage in Volts x Current in Amperes

v True Energy in KWh = No. of Revolution / Energy Meter Constant

v % Error = True Energy Actual Energy

Actual Energy

THEORY:

An induction type meter is commonly used. It consists of two magnets, the

upper and lower magnets. The upper magnet carries a pressure coil, which is made

up of a thin wire and has large number of turns. This coil has to be connected in

parallel with the supply. The lower magnet carries the current coil which is made

x

100

25

26

up of a thick wire and has only few turns. This coil is to be connected in series with

the load. An aluminum disc mounted on the spindle is placed between the upper

and lower magnets. The disc can rotate freely between the magnets. Another

permanent magnet called as brake magnet is used for providing breaking torque

on the aluminium disc.

The power consumed is measured in terms of number rotations of the disc.

For example 1800 revolutions of the disc means 1 KWH power consumed by the

load connected to the energy meter.

PRECAUTIONS:

v Single phase variac should be kept at minimum position, during starting

period.

v No load should be connected when the DPSTS is closed or opened.

PROCEDURE:

v The connections are made as per the circuit diagram.

v Rated Voltage is set in the voltmeter, by gradually varying the single phase

variac.

v Resistive load is switch ON.

v Load is gradually increased and the ammeter, voltmeter & Energy meter

readings are noted.

RESULT:

Thus the Energy consumed by a single phase resistive load was measured.

27

RESISTOR COLOUR CODING:

RESISTOR STANDARD COLOUR CODE TABLE:

Colour

Black

Brown

Red

Orange

Yellow

Green

Blue

Violet

Grey

White

Gold

Silver

None

Value Digit

0

1

2

3

4

5

6

7

8

9

Multiplier

x100

x101

x102

x103

x104

x105

x106

x107

x108

x109

x10-1

x10-2

Tolerance

1%

2%

0.5%

0.25%

0.1%

0.05%

5%

10%

20%

28

STUDY OF MEASUREMENT OF RESISTANCE USING COLOR CODING

AIM:

To study the measurement of value of resistance using color coding

REFERENCE:

1. Engineering Practices Laboratory by V. Ramesh Babu VRB Publishers.

2. Engineering Practice by M.S. Kumar D D Publications.

MATERIALS REQUIRED:

1. Resistors

2. Multimeter

THEORY:

A resistor is a passive component. It introduces resistance in the circuit.

Resistance is basic property of conducting material and is given by

R = L/ A

Where,

L

A

-

-

-

Specified resistivity.

Length of the material.

Area of cross section of material.

We have a number of type of resistors such as carbon composition, metal

film, carbon film wire wound and variable resistors.

In our laboratory carbon resistors are used. For resistance of the order of

mega ohms, we use powdered carbon mixed with a suitable building material in

the proper proportion. Carbon resistors are quite cheap, but the value of resistance

may be easily affected by atmospheric changes and is also susceptible to high

tolerance.

29

TABULATION:

Sl. No.

Resistance Value by

Colour Coding ()

Resistance Value

by Multimeter ()

30

IDENTIFICATION MARKING OF RESISTORS

Universally recognized approaches have been established to identify the

electrical values. Two such markings are

(i)

(ii)

Colour code.

Alpha numeric code.

Normally in our laboratories low wattage general purpose resistors are

used. In this colour coding method is used to identify the value of the resistance.

In our colour coding method the value of the resistance is coded on the

resistor using three or four colour bands. The first two colour band gives the first

two significant digital values. The third band gives the value of multiplier. Fourth

band gives the tolerance value.

RESULT:

Thus the value of resistor using colour coding was studied and measured.

31

CIRCUIT DIAGRAM:

Measurement of AC Voltage amplitude and frequency

AFO

CRO

TABULATION:

Maximum voltage ,

Sl.

No

Per

division

1.

2.

3.

4.

Vm in Volts

No of

divisions

Actual

Value

Peak- to-

Peak

Voltage

Vpp= 2Vm

in Volts

RMS

Voltage

Vrms

= Vm /

In Volts

Per

Time in Seconds

Frequency

Actual

Value

f = 1/T

in Hz

No of

divisions

division

32

MEASUREMENT OF AC SIGNAL PARAMETERS USING CRO

AIM:

To measure the following when a sinusoidal voltage is applied.

1.

2.

3.

4.

REFERENCE:



APPARATUS REQUIRED:

S.NO. NAME OF THE EQUIPMENT

1.

2.

3.

4.

Cathode Ray Oscilloscope (CRO)

Audio Frequency Oscillator

Bread Board

Connecting Probes, wires

TYPE

Analog

Digital

RANGE

30 MHz

2 MHz

QUANTITY

(NO.S)

1

1

1

As Required

Peak Peak Magnitude of the Voltage,

RMS Value of the Voltage

Time Period

Frequency,

FORMULA USED:

Measurement of unknown frequency = FV / FH (Hz)

= Number of loops cut in the horizontal axis

Number of loops cut in vertical axis

Where,

FV frequency of waveform given to the vertical plane

FH frequency of waveform given to the horizontal plane

VRMS = Vm / 2 (Volts)

f = 1 / T (Hz)

= 2 f (radian)

33

MODEL GRAPH: (Using CRO)

AC input Voltage:

Measurement of DC Voltage amplitude and frequency:

+

RPS (0-30V)

-

CRO

TABULATION:

SI.No.

1.

2.

3.

4.

Applied Voltage

(V)

Number of

divisions

Volt/Division

Measured

Voltage (V)

34

THEORY:

The Cathode Ray Oscilloscope is an extremely useful and versatile as laboratory

instrument for studying wave shapes of alternating currents and voltages as well as for

measurement of voltage, current and frequency. It generates the electron a high velocity,

deflects the beam to create the image and contains a phosphor beam, to screen where the

electron beam becomes visible. For accomplishing these tasks various electrical signals and

voltages are required, which are provided by the power supply circuit of the oscilloscope.

Low voltage supply is required for the heater of the electron gun for generation of electron

beam and high voltage is required for cathode ray tube to accelerate the beam. Normal

voltage supply is required for other control circuits of the oscilloscope. Electron beam

deflects in two directions horizontal on X axis and vertical on Y axis.

For measurement of direct voltage, firstly the spot is centered on the screen without

applying signal any voltage to the deflection plates. Then direst voltage to be measured is

applied between a pair of depletion plates and deflection of the spot is observed on the

screen. The magnitude of the deflection multiplied is the deflection factor gives the value of

direct voltage applied.

In case of measurement alternating voltage of sinusoidal waveform it is applied between a

pair of deflection plates and the length of the straight line is measured. Knowing be

determined the deflection sensitivity the peak to peak value of applied ac voltage can be

determined.

PROCEDURE:

1. The circuit connections are given as per the circuit diagram.

2. The sinusoidal voltage is applied with the help of AFO.

3. Readings are taken for different magnitudes and frequencies.

RESULT:

Thus the Peak Peak Magnitude of the voltage, RMS Value of the Voltage, Time

Period, Frequency are measured with help up CRO.

35

AND GATE

LOGIC DIAGRAM:

OR GATE

LOGIC DIAGRAM:

PIN DIAGRAM OF IC 7408 :


CIRCUIT DIAGRAM:

CIRCUIT DIAGRAM:

TRUTH TABLE:

S.No

1.

2.

3.

4.

INPUT

AB

00

01

10

11

OUTPUT

Y=A.B

0

0

0

1

TRUTH TABLE:

S.No

1.

2.

3.

4.

INPUT

A

0

0

1

1

B

0

1

0

1

OUTPUT

Y=A+B

0

1

1

1

36

STUDY OF BASIC LOGIC GATES

AIM:

To verify the truth table of basic logic gates of AND, OR, NOT, NAND,

NOR, EX-OR gates.

REFERENCE:



APPARATUS REQUIRED:

S.No

1.

2.

3.

4.

5.

6.

7.

8.

Name of the Apparatus

Digital IC trainer kit

AND gate

OR gate

NOT gate

NAND gate

NOR gate

EX-OR gate

Connecting wires

IC 7408

IC 7432

IC 7404

IC 7400

IC 7402

IC 7486

As required

Range

Quantity

1

1

1

1

1

1

1

THEORY:

a. AND gate:

An AND gate is the physical realization of logical multiplication operation.

It is an electronic circuit which generates an output signal of 1 only if all

the input signals are 1.

b. OR gate:

An OR gate is the physical realization of the logical addition operation. It is

an electronic circuit which generates an output signal of 1 if any of the

input signal is 1.

37

NOT GATE

LOGIC DIAGRAM:

NAND GATE

LOGIC DIAGRAM:

PIN DIAGRAM OF IC 7404:


CIRCUIT DIAGRAM:

CIRCUIT DIARAM:

TRUTH TABLE:

S.N

o

1.

2.

INPUT

A

0

1

OUTPUT

Y = A

1

0

TRUTH TABLE:

S.No

1.

2.

3.

4.

INPUT

AB

00

01

10

11

OUTPUT

Y = (A. B)

1

1

1

0

38

c. NOT gate:

A NOT gate is the physical realization of the complementation

operation. It is an electronic circuit which generates an output signal

which is the reverse of the input signal. A NOT gate is also known as

an inverter because it inverts the input.

d. NAND gate:

A NAND gate is a complemented AND gate. The output of the NAND

gate will be 0 if all the input signals are 1 and will be 1 if any one of

the input signal is 0.

e. NOR gate:

A NOR gate is a complemented OR gate. The output of the OR gate

will be 1 if all the inputs are 0 and will be 0 if any one of the input

signal is 1.

f. EX-OR gate:

An Ex-OR gate performs the following Boolean function,

A

B = ( A . B ) + ( A . B )

It is similar to OR gate but excludes the combination of both A and B

being equal to one. The exclusive OR is a function that give an output

signal 0 when the two input signals are equal either 0 or 1.

PROCEDURE:

v Connections are given as per the circuit diagram

v For all the ICs 7th pin is grounded and 14th pin is given +5 V supply.

v Apply the inputs and verify the truth table for all gates.

39

NOR GATE

LOGIC DIAGRAM:

EX-OR GATE

LOGIC DIAGRAM



CIRCUIT DIAGRAM:

CIRCUIT DIAGRAM:

TRUTH TABLE:

S.No

1.

2.

3.

4.

INPUT

AB

00

01

10

11

OUTPUT

Y = (A + B)

1

0

0

0

TRUTH TABLE:

S.No

1.

2.

3.

4.

INPUT

AB

00

01

10

11

OUTPUT

Y=AB

0

1

1

0

40

RESULT:

The truth table of all the basic logic gates were verified.

41

CIRCUIT DIAGRAM:

Half Wave Rectifier:

P

IN 4007

230 V, 50 Hz

1 Supply

1 K

100 F

CRO

N

Step-down Transformer

(0 12V)

Full Wave Rectifier:

P

D1

230 V, 50 Hz

1 Supply

D4

N

D3

1 K

100 F

CRO

D2

TABULATION:

Without Filter

Rectifier

Half Wave Rectifier

Full Wave Rectifier

Vm (V)

T (mS)

Vm (V)

With Filter

T (mS)

Charging

Discharging

42

HALF WAVE AND FULL WAVE RECTIFIER

AIM:

To obtain the output of Half wave and Full Wave rectifier and to plot

the characteristics.

REFERENCE:



APPARATUS REQUIRED:

S.NO. NAME OF THE EQUIPMENT

1

2

3

4

5

6

7

Diode

Resistor

Capacitor

Transformer

Step-down

TYPE

IN 4001

1 K

100 F

230 V /

(12 0 12) V

CRO

Bread Board

Connecting wires and probe

Analog

30 MHz

1

1

As Required

RANGE

QUANTITY

(NO.S)

4

1

1

1

THEORY:

Half wave rectifier converts alternating voltage into unidirectional

pulsating voltage. The half wave rectifier circuit using a diode with a load

resistance R. The diode is connected in series with the secondary of the

transformer and the load resistance R, the primary of the transformer is being

connected to the supply mains. The AC voltage across the secondary winding

changes polarities after every half cycle. During the positive half cycles of the

input AC voltage i.e. when upper end of the secondary winding is positive

with respect to its lower end, the diode is forward biased and therefore

43

WAVEFORMS:

Vin (V)

Vm

0

Time

Vout (V)

Output of Half Wave Rectifier without filter

0

Vm

Time

Output of Half Wave Rectifier with filter

0

Time

filter

Vm

Output of Full Wave Rectifier without

0

Vm

filter

Time

Output of Full Wave Rectifier with

0

Time

44

current conducts. During the negative half cycles of the input AC voltage i.e.

when lower end of the secondary winding is positive with respect to its upper

end, the diode is reverse biased and does not conduct. Thus for the negative

half cycles no power is delivered to the load. Since only one half cycles of the

input wave is converted as output, it is called as Half Wave Rectifier.

In Full Wave Rectifier the diode D2 and D4 will conduct during

the positive half of the input signal and during the negative half cycle of the

input signal the diode D1 andD3 conducts. Hence both the half cycles are

converted into output and the efficiency is high compared with the half wave

rectifier.

PROCEDURE:

1. Circuit connections were given as per the circuit diagram.

2. Input waveforms magnitude and frequency was measured with the

help of CRO.

3. Supply is switched ON and the output waveform was obtained in the

CRO.

4. Output waveforms magnitude and time period was measured.

5. Graphs were plotted for Half wave and Full wave rectifier outputs.

RESULT:

Thus the output of Half wave and Full wave rectifiers were obtained

and the curves were plotted.

45

46

MEASUREMENT OF RESISTANCE TO EARTH OF ELECTRICAL

EQUIPMENT

AIM:

To measure the resistance to earth / insulation resistance of the order of

mega ohms.

REFERENCE:



THEORY:

Megger is the equipment used in this experiment. It is an instrument

for testing the insulation resistance of the order of mega ohms.

PRINCIPLE:

A megger consists of an EMF source and a Voltmeter. The voltmeter

scale is calibrated in ohms. In measurement, the EMF of the self contained

source should be equal that of the source used in calibration. The deflection of

the moving system depends on the ratio of the currents in the coils and is

independent of the applied voltage. The value of unknown resistance can be

found directly from the scale of the instrument. Figure shows the detailed

diagram of a megger. It consists of hand driven dc generator and ohmmeter, a

small permanent magnet. Hand driven dc generator generates a EMF about

500V. The permanent dc meter has two moving coils. First one is deflecting

coil and another one controlling coil. The deflecting coil is connected to the

generator through a resistor R. The torque due to the two coils opposes each

other. It consists of three terminals E, L and G.

OPERATION:

When the terminals are open circuited, no current flows through the

deflecting coil. The torque due to the controlling coil moves the pointer to one

end of the scale. When the terminals are short circuited, the torque due to the

controlling coil and the pointer is deflected to the other end of the scale, i.e.

47

48

zero mark. In between the two extreme positions the scale is calibrated to

indicate the value of unknown resistance directly. The unknown insulation

resistance is connected across E and L terminals. The effective insulation

resistance is the combination of insulation volume resistance and surface

leakage resistance. The guard wire terminal makes the surface leakage current

to by pass the instrument hence only insulation resistance is measured.

RESULT:

Thus the resistance to earth / insulation resistance of the order of mega

ohms can be measured.

49

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