Electrical and Electronics Engineering Lab Manual

8/13/2019 Electrical and Electronics Engineering Lab Manual

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ELECTRICAL AND ELECTRONICS ENGINEERING LAB

DEPARTMENT OF

ELECTRICAL AND ELECTRONICS ENGINEERING

ACADEMIC YEAR 2012-2013

II B.Tech MECH I-SEMESTER

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PREFACE

The significance of the Electrical and Electronics Engineering Lab is

renowned in the various fields of engineering applications. For an Mechanical

Engineer, it is obligatory to have the practical ideas about the Electrical and

Electronics Engineering. By this perspective we have introduced a Laboratory

manual cum Observation for Electrical and Electronics Engineering Lab.

The manual uses the plan, cogent and simple language to explain the

fundamental aspects of Electrical and Electronics Engineering in practical. The

manual prepared very carefully with our level best. It gives all the steps in

executing an experiment.



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ACKNOWLEDGEMENT

It is one of lifes simple pleasures to say thank you for all the help that one

has extended their support. I wish to acknowledge and appreciate Assoc Prof Saleem

Pasha, Foreman. P Prabhu Dass, and G.Suresh for their sincere efforts made towards

developing the Electrical and Electronics Engineering manual. I wish to thank

students for their suggestions which are considered while preparing the lab manual.

I am extremely indebted to Sri.Col Dr. T. S. Surendra, Principal and

Professor, Department of Electrical and Electronics Engineering, BVRIT for his

valuable inputs and sincere support to complete the work.

Specifically, I am grateful to the Management for their constant advocacy

and incitement.

Finally, I would again like to thank the entire faculty in the Department and

those people who directly or indirectly helped in successful completion of this work.

(Prof. N. BHOOPAL)HODEEE



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GUIDELINES TO WRITE YOUR OBSERVATION BOOK

1. Experiment Title, Aim, Apparatus, Procedure should be on right

side.

2. Circuit diagrams, Model graphs, Observations table, Calculations table should beleft side.

3. Theoretical and model calculations can be any side as per your convenience.

4. Result should always be in the ending.

5. You all are advised to leave sufficient no of pages between experiments

for theoretical or model calculations purpose.



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DOS AND DONTS IN THE LAB

DOS:-

1. Proper dress has to be maintained while entering in the Lab. (Boys Tuck in and

shoes, girls with apron)

2. All students should come to the Lab with necessary tools. (Cutting Pliers 6,

Insulation remover and phase tester)

3. Students should carry observation notes and record completed in all aspects.

4. Correct specifications of the equipment have to be mentioned in the circuit

diagram.

5. Student should be aware of operating equipment.

6. Students should be at their concerned experiment table, unnecessary moment is

restricted.

7. Student should follow the indent procedure to receive and deposit the equipment

from the Lab Store Room.

8. After completing the connections Students should verify the circuits by the Lab

Instructor.

9. The reading must be shown to the Lecturer In-Charge for verification.

10. Students must ensure that all switches are in the OFF position, all the

connections are removed.

11. All patch cords and stools should be placed at their original positions.

DONTs:-

1. Dont come late to the Lab.

2. Dont enter into the Lab with Golden rings, bracelets and bangles.

3. Dont make or remove the connections with power ON.

4. Dont switch ON the supply without verifying by theStaff Member.

5. Dont switch OFF the machine with load.

6. Dont leave the lab without the permission of the Lecturer In-Charge.



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JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY

II Year B.Tech MECH I-Sem Academic year 2012-2013

L T/P/D C

0 -/3/- 2

(53604) ELECTRICAL AND ELECTRONICS ENGINEERING LAB

SECTION-A: Electrical Engineering:

The following experiments are required to be conducted as compulsory experiments.

1. Swinburnes Test on DC shunt machine (Predetermination of efficiency of a given

DC Shunt machine working as motor and generator).2. OC & SC tests on Single-phase transformer (Predetermination of efficiency and

regulation at given power factors).

3. Brake test on 3-phase Induction motor (performance characteristics).

4. Regulation of alternator by synchronous impedance method.In addition to the above

four experiments, any one of the experiments from the following list is required tobe conducted

5. Speed control of DC shunt motor by

A)Armature voltage control method

B)Field flux control method.

6. Brake test on DC shunt motor.

SECTION-B: Electronics Engineering:

1. Transistor CE Characteristics (Input and Output)2. Full wave Rectifier With and without Filters

3. CE Amplifiers4. RC phase shift Oscillator5. Class A power Amplifier.

6. Microprocessor.



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Expt No: 1

SWINBURNE S TEST ON DC SHUNT MACHINE

PREDETERMINATION OF EFFICIENCIES

Aim:To perform no load test on dc m otor and to predetermin e the

ef f ic iencies o f the m achine act ing as a mo tor and generator .

Equipment:

S.No Apparatus Type Range qty

1 Voltmeter MC 0-250v 1

2 Voltmeter MC 0-30V 13 Ammeter MC 0-5A 1

4 Ammeter MC 0-2A 1

5 Rheostats Wire wound 400 /1.7A 1

Wire wound 100 /5A 1

Name plate details(Tobe noted down from the Machine)



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Circuit diagram:

Circuit diagram to find out Ra:



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Theory:It is simple indirect method in which losses are measured separately

and the efficiency at any desired load can be predetermined. This test applicable to

those machines in which flux is practically constant i.e. shunt and compound wound

machines. The no load power input to armature consist iron losses in core, friction

loss, windage loss and armature copper loss. It is convenient and economical

because power required to test a large machine is small i.e. only no load power. But

no account is taken the change in iron losses from no load to full load due to

armature reaction flux is distorted which increases the iron losses in some cases byas 50%

Procedure:

1.Make connections as per the circuit diagram.

2.Show the connections to the lab instructor.3.Keeping both rheostats at minimum, Start the motor with the help of starter,and

by adjusting field rheostat bring the motor to rated speed.4. Note down all the meter readings at no load..

5.Do necessary calculations and find out the efficiency of the Machine as a motorand as a generator.

5.Draw the graphs between output Vs efficiency of the Machine as a generator andas a motor..

Observations:

IL IF IA V N

For Ra

S.NOV I Ra=V/I



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Tabular Column to find out efficiency:

GENERATOR:

Motor

Model calculations:

No load input=V IL

No load armature copper losses =Ia 2Ra =(IlIf)2Ra

Constant losses Wc=V l(Il-If)2Ra

Efficiency as a motor:

I= Assumed load current

Motor i/p=VIIa=IL-If

Motor armature losses=I2a .Ra

Total losses=I2aRa+ Wc

Efficiency of motor= VI- I2aRa+ Wc / VI x 100

S.No Voltage=V

LoadCurrent=IL

ArmatureCurrent Ia=(IL+If)

ArmatureCu loss=Ia XIaXRa

Total lossesWt=Wc+

IaXIaXRa

Output=VxIL

Input=Output+totallosses=VxIL+Wt

=

OutputInput.

S.No Voltage=V

LoadCurrent=IL

ArmatureCurrent Ia=(IL-If)

ArmatureCu loss=Ia XIaXRa

Total lossesWt=Wc+

IaXIaXRa

Input=VxIL

Output=Input-totallosses=VxIL-Wt

=

OutputInput.



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Efficiency as generator:

I=assumed load current

Generator O/P =VI

Generator armature cu. Losses= I2a .Ra

Total losses= I2aRa+ Wc

Efficiency of generator=VI / VI+ I2aRa+ Wc

Expected graphs:-

Efficiency Vs Output

Results



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Expt No : 2

OC & SC TESTS ON 1- TRANSFORMER

Aim: To conduct OC & SC tests on the given 1- Transformer and to calculate itsequivalent circuit parameters, efficiency & regulation.Name plate details:

1- TRANSFORMER

Capacity 3 KVA

I/P voltage 230V

I/P current 13.04A

O/P voltage 115V

O/P current 26.08A

Frequency 50Hz

Apparatus required:

S.NO DESCRIPTION RANGE TYPE QTY

OC TEST

1 Voltmeter 0-150V M.I 1 No

2 Ammeter 0-2.5A M.I 1 No

3 Wattmeter 2.5A/150V

Dynamo

meter

(LPF)

1 No

4 Auto T/F 230V/0-270V,

8A

1- wire

wound

1 No

5 Fuses 5A - 2

Nos



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(0-2)A

(0-150)V

1- 230V

50 HzAC

Supply

Ph

N

115V

230V

1 -Transformer3KVA, 230V/

Open

Circuit

DPST

Variac

3KVA, 230V/ (0-

2A, 150V, 60W,

LM

C

Fig -1

A

230V

115V

(0-15)A

(0-50)V

MI

1-

230V

50 HzAC

Supply

Ph

N1 -Transformer

Short

Circuit

DPST

Variac

3KVA, 230V/ (0-

15A, 50V, 600W,

C

V

A

OPEN CIRCUIT TEST:-

SHORT CIRCUIT TEST:



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Theory: Transformer is a static device which transfers electrical powerfrom

one circuit to another circuit either by step up or step down the voltage

with corresponding decrease increase in the current, with outchanging the

frequency.

OC Test

The main aim of this test is to determine the Iron losses & No- load

current of the T/F which are helpful in finding Ro & Xo.In this test generally

supply will be given to primary and secondary kept open. Since secondary is

opened a small current(magnetizing current will flow and it will be 5 to 10%

of full load current. The wattmeter connected in primary will give directly the

Iron losses (core losses).

SC Test:

The main aim of this test is to determine the full load copper losses which is

helpful in finding the R01, X01, Z01, efficiency and regulation of the T/F.

Apparatus Required for SC Test


2 Ammeter 0-5A M.I 1 No

3 Wattmeter 5A/50V

Dynamo

meter

(UPF)

1 No

4 Auto T/F 230V/0-270V,

8A

1- wire

wound

1 No

5 Fuses 5A - 2

Nos



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Generally low voltage side will be short circuited and supply will be given to

high voltage side & it will be of 5-10% of the rated voltage. The wattmeter

connected in primary will give directly the full load copper losses of the T/F.

Procedure :

OC Test:

1) Give connections as per the circuit diagram.

2) Switch-ON the supply and apply rated voltage to the

3) primary of the winding by using the auto transformer.

4)

Note the readings of Ammeter, Voltmeter & Wattmeter



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SC Test:

1) Give connections as per the circuit diagram.

2) Switch-ON the supply and vary the Dimmerstat till rated

3) full load current flows through transformer.

4) Note the readings of Ammeter, Voltmeter & Wattmeter

Graph: A graph is drawn between P.F and % regulation by taking P.F on

X- axis and % regulation on Y-axis.

Observations:

O.C Test: S.C Test:

Calculations:

Load Cu losses Total losses I/P power O/P power %

Full

V0 I0 W0

volt ampere watt

VSC ISC WSC

volt ampere Watt



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PRECAITIONS: 1) The Dimmer stat should be kept at minimum O/P

position initially.

2) In OC test, rated voltage should be applied to the

Primary of the Transformer.

3) In SC test, the Dimmer stat should be varied up to the

rated load current only.

4) The Dimmer stat should be varied slowly & uniformly.

Result:

P.F% Regulation

lag lead



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CIRCUIT DIAGRAM:-

10A, 600V, 3KW,

3- 415V

50 HzAC

Supply

3- 415V

50 HzAC

Supply

R

Y

B

M L

VC

A

V

C

V

L

L

L

L

B

B

A

A

C

C

Y/Starter

(0-15)A

(0-600)V

10A, 600V, 3KW,

A

B

B

A

C

C

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Expt No: 3

BRAKE TEST ON 3 - INDUCTION MOTOR

Aim: To conduct a brake test on the given 3 -Slip ring Induction motor and to

draw its performance Characteristics.

Nameplate details:

3 -INDUCTION MOTOR

Capacity 5 H.P

Voltage 415V

Current 7.5A

Speed 1500rpm

Frequency 50Hz

RotorVoltage 200V

current 11A

Apparatus required:


1 Starter415V,

15AD.O.L 1 No

2 Ammeter 0-10A M.I 1 No


4 Wattmeters 10A/600VDynamo

meter

2

Nos

5 Fuses 10A -3

Nos

6 Tachometer

0-

50000rpm Digital 1 No

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Precautions: 1) There should not be any load on the motor initially.

2) The brake drum should be filled with water to cool it.

3) If the wattmeter shows negative deflection, reverse either

pressure coil or current coil and take that reading as

negative.

4) The rotor external resistance should be kept at max

resistance position initially.

Theory: As a general rule, conversion of electrical energy to mechanical energy

takes place in to the rotating part on electrical motor. In DC motors, electrical

power is conduct directly to the armature, i.e, rotating part through brushes and

commutator. Hence, in this sense, a DC motor can be called as conduction

motor. However, in AC motors, rotor does not receive power by conduction but

by induction in exactly the same way as secondary of a two winding T/F receives

its power from the primary. So, these motors are

known as Induction motors. In fact an induction motor can be taken as rotating

T/F, i.e, one in which primary winding is stationary and but the secondary is free.

The starting torque of the Induction motor can be increase by improving its p.f

by adding external resistance in the rotor circuit from the stator connected rheostat,

the rheostat resistance being progressively cut out as the motor gathers speed.

Addition of external resistance increases the rotor impedance and so reduces the

rotor current. At first, the effect of improved p.f predominates the current-

decreasing effect of impedance. So, starting torque is increased. At time of starting,

external resistance is kept at maximum resistance position and after a certain time,

the effect of increased impedance predominates the effect of improved p.f and so

the torque starts decreasing. By this during running period the rotor resistance

being progressively cut-out as the motor attains its speed. In this way, it is possible

to get good starting torque as well as good running torque.

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Procedure: 1) Give all the connections as per the circuit diagram.

2) SwitchON the supply and press the ON button of the

starter.

3) Now put the rotor external resistance switch to run

position in steps & slowly.

4) Note the no-load readings of ammeter, voltmeter,

wattmeter, speed & loads.

5) Gradually increase the load on the motor by tightening the

hand-swivels and note the corresponding meters

readings.

6) Remove the load completely & Switch-Off the power.

Graph: A graph is drawn b/w O/P power in watts (on X-axis) verses speed,

torque, current, slip, efficiency & p.f (on Y-axis).

Observations:

Volt

meter

Rea-

ding

Am-

meter

reading

I/P=W1 W2 ForceNet

Force

Torq

-ueSpeed O/P % % Slip p.f

V A W1W2

F1 F2 F1~F29.8x

Fe.ReN

2 NT/

60

O/p

/i/p

X 100

Ns-Na

/Ns

Volt ampere watt Watt kg kg kg FxRe rpm watt - - -

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Thickness of the belt, t =

Circumference of the drum, 2 R =

Radius, R = C/2 =

Effective radius, Re= R + t/s =

Expected Graphs

Result:

0

N Vs O/P

T Vs O/P

Vs O/P

X

Y

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4. REGULATION OF ALTERNATOR BY SYNCHRONOUS IMPEDANCE

METHOD

Aim: To conduct OC test & SC test n the given 3 -Alternator and to

determine its regulation by synchronous impedance method.

Nameplate details:

Apparatus required:


DESCRPTION D.C MOTOR 3 -ALTERNATOR

Capacity 5 H.P 3 KVA

Voltage 220V 415V

Current 19A 4.2ASpeed 1500 Rpm 1500 Rpm

Excitation 220V, 1.5A 220V, 1.4A

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3 point starter OC TestDPST Switch 3- Alternator TPST Switch

+

230 V

DCSupply

F

FF

L FA

400 /

1.7A

A

AA

M

FA

FAA

B

R

N

Y

V(0-300)V

MI

Fuse +

230 V400 /

+A

DC

Supply1.7A (0-1)A

MC

Fuse

3 point starter SC TestDPST Switch 3- Alternator TPST Switch

+

230 V

DC

Supply

F

FF

L FA

400 /

1.7A

A

AA

M

FA

FAA

B

R

N

Y

A

(0-10)A

MI

Fuse +

400 /

+A

230 V

DC

Supply

1.7A (0-1)A

MC

Fuse

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Precautions:

Theory:

1) Operate the 3-point starter slowly & uniformely.

2) Keep the speed of the prime mover to its rated value through

out the experiment.

3) In OC test, there should not be any load on Alternator.

4) In SC test, the SC current should not exceed its rated value.

Alternator is a machine, which converts mechanical energy to

electrical energy. Regulation of an Alternator can be calculated by synchronous

impedance method. In OC test the terminals of the alternator are kept opened and a

voltmeter is connected. Keeping speed constant, a relation b/w field current & open

circuit voltage are obtained. In SC test, the terminals are short circuited with a

suitable ammeter & a relation b/w field current & short circuit Current are

obtained.

Voltage regulation:

It is defined as the rise in terminal voltage of an isolated

Machine when full load is thrown off w.r.t voltage on the full load,

when speed & excitation remaining constant.

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Now, Syn.Impedance (ZS) = OC voltage / SC current

XS= Z2S- R2a

From fig. EO= OB2+ BD2

= (Vcos +IRa)2+ (Vsin +IXS)2

% Regulation = [(E0-V) / V] 100

Procedure: OC test:

1) Give all connections as per the circuit diagram.

2) Switch-ON the supply & by varying the starter, prime mover

speed is adjusted to rated.

3) Now keeping the field current at zero, note the induced emf in

armature duo to residual Magnetism.

4) By slowly varying the potential divider, field current is increased

& corresponding emf Induced is noted up to above 20% of rated

voltage.

SC test:

1) Give all connections as per the circuit diagram.

2) Switch-ON the supply & by varying the starter, prime mover

speed is adjusted to rated.

3) By slowly varying the potential divider, field current is increased& corresponding short Circuit current is noted up to rated value.

To find armature resistance (Ra):

Give the connections as per diagram and by slowly varying the

rheostat, note the values of ammeter & voltmeter up to some

value and average them.

Graph: 1) A graph is drawn b/w Ifand V which is known as OC

curve, by taking Ifon X-axis and V on Y-axis.

2) A graph is drawn b/w Ifand ISCwhich is known as SC

curve, by Taking Ifon X-axis and ISCV on Y-axis.

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Observations:

OC Test: SCTest:

Field OC Field SC

current If voltage current If current

Armature resistance:

Voltage current Resistance Ra

Expected Graphs:

Result:

If 2

1

Isc

SCC

XO

Eo

Y

If

OCC

% Voltage

Regulation

Leading PF Lagging PF

If1

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5. SPEED CONTROL OF DC SHUNT MOTOR

Aim:To conduct speed controls on DC shunt motor.

The methods are1.Armature voltage control method 2. Flux control method

Apparatus:

S.No Equipment Range Type Qty

1 Ammeter 0-5A0-2A

MCMC

1No1No

2 Voltmeter 0-250V MC 1No

3 Rheostats100 /5A

Wire wound 1NO

400 /1.7A Wire wound 1No

4 Tachometer 0-2000rpm Digital 1No

5 Connecting Wires LS

Circuit diagram:

Theory:

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i) Armature voltage control method:For a load of constant Torque, the speed is proportional to the applied to the armature. Therefore

speed voltage characteristic is linear and is a straight line. As the voltage is decrease across thearmature the speed falls. This method gives speeds less than rated speeds.

Eb N Eb NV-Ia(Ra+R) NAs the voltage is decreased speed decreases.

ii) Flux Control Method:With rated voltage applied to the motor, the field resistance is increased i.e field current is

decreased. I t is observed that speed increases.Eb/ N N Eb/If

The characteristics If Vs N is inverse (or) if it is hyperbola.

Procedure:

i) Armature Voltage Control Method

1) Make connections as per the circuit diagram.2) Show the connections to the lab instructor.

3) Keeping both rheostats at minimum, Start the motor with the help of starter,and by adjustingfield rheostat bring the motor to rated speed.

4) By increasing armature circuit rheostat in steps note down voltage, Ia and speed at everystep.

5) The corresponding graph is draw between armature Voltage Vs speed.

ii) Flux Control method:

1) The machine run at its rated speed and rated voltage obtained.2) The voltage is kept constant and for different vales of field currents the speeds are

noted.

Tabular Column:Armature Voltage Control M ethod:

S.No Armature

Voltage in V

Armature

current=Ia

in A

Speed

in RPM

Eb=V-IaRa in V

F lux Control Method:

S.No Field Current Speed in RPM

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Expected graphs:-

N vs If

N vs Va(Armature voltage)

Result:

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6. BRAKE TEST ON DC SHUNT MOTOR. DETERMINATION OF ITS PERFORMANCECURVES

Aim:To conduct brake test on DC Shunt motor. And to determine its performance curves.

Apparatus:

S. No Equipment Range Type Qty

1. Voltmeter 0-250V M.C. 1

2. Ammeter 0-20A M.C 1

3 Ammeter 0-1/2A M.C 1

4 Rheostat 400 /1.7A Wire wound 1

5. Tachometer Digital type 1

6. Connecting wires

Name plate details:

Circuit diagram:

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Theory:When if is required to determine directly efficiency if comparatively small motors, the

motor is loaded directly by means of Mechanical Break. Hence in the case of shunt motor thereis no drastic change in speed. The Torque T = (S1~S2) g. rNm. where S1S2 is the spring

balance reading, r = Break drum Radius

and g=9.81.

P = Power developed. Hence directly the efficiency = Po/ Pix 100

Procedure:-

01. Make Connections as per the circuit diagram.02. Start the motor with the help of the starter.

03. Then bring the motor to rated speed by adjusting field rheostat.

04. Put the mechanical load on the motor in steps and note down corresponding readings ofall meters.

05. Do calculations accordingly.

Tabular columns :

S.No Voltage

(V)

Current

(I)

Speed

(N)

Spring

Balance

Readings

Torque=

9.8 1(S1~ S2)

.r -Nm

Pout=

2 nT/60-Watts

Pin=

Vi - Watts

Eff =

op/ip

x100.

S1 S2

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EXPECTED GRAPHS:-

Ta vs Ia.

N vs Ia.

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N vs T

Vs O/P

Result:

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PART-BExpt No: 1

TRANSISTOR CE CHARACTERISTICS (INPUT AND OUTPUT)

AIM: To plot the transistor characteristics of common emitter configuration

EQUIPMENT REQUIRED:

Regulated Power Supply 030V(Dual)DC Ammeter 0100 UA,0-10 mA. DC

Voltmeter 0 -- 1V, 0--30V

COMPONENTS REQUIRED:

Transistor BC 107,BC 547Resistor 1K , 39K

BreadboardConnecting wires

THEORY:

PROCEDURE:

INPUT CHARACTERISTICS:

1. Connect the circuit as shown in Figure. Use milli ammeters of

proper range

2. For input characteristics, first fix the collector - emitter voltage VCE

at 5 volts. Now vary base-emitter voltage VBE in steps of 0.1 volts

and note down the corresponding emitter current IB.

3. Repeat the above procedure for collectoremitter voltage VCE at

10V, 15V etc.

4. Plot the graph between base-emitter voltage VBE and Base current

IB for a constant collectoremitter voltage VCE.

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Circuit diagram:

5. Find the hparameters: (a) hre: Reverse voltage gain

(b) hie : Input impedance

OUTPUT CHARACTERISTICS:

1. For out put characteristics, first fix the Base current IB at 20 A

.Now vary collector-emitter voltage VCE in steps of 1volts and note

down the corresponding collector current IC

2. Repeat the above procedure for Base current IB at 30 A , 40 A.

3. Plot the graph between collector Emitter voltage VCE and

collector current IC for a constant Base current IB.

4. Find the hparameters : (a) hfe = Forward current gain.

hoe = Output admittance.

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MODEL GRAPHS: Input characteristics

Output Characteristics

Tabular Form:

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Input characteristics:

Output characteristics:

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CALCULATIONS:

1. Input dynamic resistance, ri = tconsVIV

CE

B

BE tan

2. Output ac resistance , ro= AIIV

B

B

CE ____

3. DC Current gain , _____VII

CE

B

C

DC

4. AC Current gain , tconsVII

CE

B

C tan_____

RESULT:

hie =

hfe=

hre =

hoe =

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EXPERIMENTS2

RECTIFIERS WITH OUT FILTERS (FULL WAVE & HALF WAVE)

RECTIFIERSWITH FILTERS (FULL WAVE & HALF WAVE)

AIM: Study of rectifiers with and with out capacitance filters half waverectifier and full wave rectifier. To Find its. Percentage of

regulation and Ripple factor.

EQUIPMENT REQUIRED:

CRO 020 M hz (Dual trace) DCVoltmeter 0--30V


Diodes (1N 4007) 2Nos.Resistor (Variable) 10K Breadboard

Connecting wires

THEORY:

PROCEDURE:

1. Connect the circuit diagram as shown in Figure.12. Connect CRO across the load. Keep the CRO switch in ground mode and

observe the horizontal line and adjust it to the X- axis.3. Switch the CRO in to DC mode and observe the waveform. Note down its

amplitude, Vm and frequency from the screen along with its multiplicationfactor.

4. Calculate Vdc using the relation Vdc =vm

5. Switch the CRO in to AC mode and observe the waveform. Note down its

amplitude, Vm and frequency from the screen along with its multiplicationfactor.

6. Calculate Vac using the relation: V2 rms = V2ac +V2

dc

7. Calculate the ripple factor from the given formula: =v

v

dc

ac

Circuit diagram:

Half wave rectifier with out capacitor:

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Half wave rectifier with capacitor:

Full wave rectifier with out capacitor:

Full wave rectifier with capacitor:

8. Remove the load and measure the output DC voltage (DC mode) and calculate the

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percentage of voltage regulation using the formula:

Percentage regulation = 100v

vvnoload

loadnoload %

9. To measure ratio of rectification, observe the power (DC and AC) using wattmeter acrossthe load. The ratio of rectification is given by Pac/Pdc

Model graph:

Half wave rectifier model graph:

Full wave rectifier model graph:

With Capacitor:1. Calculate the value of R by assuming C = 1000 F and f = 50 Hz using the

formula = 1/ 4 (3fRC) (assume as 0.002 or any small value)

2. Connect the capacitor across the load resistance and proceed with the aboveProcedure from steps 19 as shown above. Follow the above-

mentioned procedure for Full Wave rectifier.

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Calculations:

Half wave rectifiers:

1. Vrms=2

vm Vavg=vm

2. ripple factor 12

2

v

v

avg

rms

3. Efficiency =

4. Percentage efficiency =5. Peak inverse voltage (PIV) = Vm

6. Form factor = Vrms/ Vavg7. Peak factor = Vpeak/ Vrms

Full wave rectifiers :

1. Vrms=

2

vm

2. Vavg =vm2

3. ripple factor 12

2

v

v

avg

rms

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CIRCUIT DIAGRAM :

CE AMPLIFER

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CE AMPLIFIER

AIM: Design and test a common emitter amplifier and find the followingparameters.

1. Current gain2. Voltage gain3. Bandwidth

4. Input and output impedances.

EQUIPMENT REQUIRED:

Regulated Power Supply 030VCRO 20 MHz(Dual trace)

Function generator 01 Mhz


Transistor BC 107,BC 547Resistor designed values

BreadboardConnecting wires

THEORY:

AmplifierDesign:

AVS= -hFeRleeff /((hie||RB)+RS) -hFeRleeff/(hie+RS) ---------(1)Assume, VCE=VCC/2(transistor active)

Effective load resistance is given by,Rleff=RC||RLEmitter resistance is given by,re=26mv/IE

hie= reWhere re is internal resistance of the transistorhie= hfe re ,VE=Vcc/10On applying KVL to output loop we get

Vcc=Ic.Rc+VcE+IE.RE Where

VE=IE.RE,Find Rc? Fromequation (1),find RLSince IB is very small when compare with Ic

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In put Coupling capacitor is given by Xci={[hie+(1+hfe)RE]||RB}/10

Xci=1/2 f Ci

Find Ci?

Out put coupling capacitor is given by, XCO=RC||RT/10Xco=1/2 fCoFind Co ?By-pass capacitor is given by

Xce=RE/10

XCE=1/2 fCEFind CE=?

PROCEDURE:

1. Connect the circuit diagram as shown in Figure.1.

2. Keep VS at 50 mv, using the signal generator.

3. Keeping the input voltage constant, vary the frequency from 0 to 1

Mhz in regular steps and note down the corresponding output voltage.

4. Plot the graph between gain (dB) and frequency.

5. Find the input and output impedances.

Input impedance, Zi = Vi Rs / (Vs+Vi)

Output impedance, Zo Calculate the bandwidth from the graph.

6. Note down the bandwidth, input and output impedances.

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Tabular form:

Input voltageVs=

S No. Frequency Vo (volt) Gain =

Vo/Vs

Gain (dB) = 20 log

(Vo/Vs)

Result:

1. Input impedance

2. Output impedance3. Gain (Mid band)

4. Bandwidth

DISCUSSION QUESTIONS:

1. Define Amplification?

2. What is biasing? Why it is necessary?

3. Mention different types of Biasing?

4. Mention the applications of CE Amplifier, Justify?

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Circuit Diagram:

RC PHASE SHIFT OSCILLATOR

MODEL GRAPH:

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RC PHASE SHIFT OSCILLATOR

AIM: To design and construct a RC Phase Shift Oscillator for a given operating

Frequency.

EQUIPMENT REQUIRED:Regulated Power Supply 030VCRO 20 MHz (Dual trace)


Transistor BC 107Resistor designed values

Capacitors designed valuesBreadboard

Connecting wires

THEORY:

Design :

Fo=1Khz,C=0.01uf,Vcc=12V

F=1/2 (6RC),Find R?, (s)=-1/29,=1/ =-29

AmplifierDesign:

AV=-hFeRleeff/hie (AV=29,design given)Assume, VCE=VCC/2(transistor active)

Effective load resistance is given by,Rleff=RC||RLEmitter resistance is given by,re=26mv/IE

hie= reWhere re is internal resistance of the transistorhie= hfe reVE=Vcc/10On applying KVL to output loop we get

Vcc=Ic. Rc+VcE+IE.RE

Whre VE=IE.RE

Find Rc?Since IB is very small when compare with Ic

Ic IE RE=VE/IEVB=VBE+VE

VB=Vcc(RB2/(RB1+RB2))

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S=1+(RB/RE)

Find RB ?

RB=RB1||RB2

Find RB1 and RB2

Input coupling capacitor is given by Xci={[hie+(1+hfe)RE]||RB}/10Xci=1/2 fci,Find Ci?,Xco=1/2 fco,Find Co ?

By-pass capacitor is given by

Xce=RE/10,XCE=1/2 fCE

Find CE=?

PROCEDURE:

1. Connect circuit diagram as shown in Figure2. Switch on the power supply and observe the output on the

CRO (Sine wave).

3. Note down the practical frequency and compare it with itstheoretical frequency.

TABULAR FORM:

Sl. No. Theoretical time period Practical time period

RESULTS:

Theoretical time period and frequency: --------- ---------

Practical time period and frequency: ---------- --------

DISCUSSION QUESTIONS:

1. It s the main difference between an alternator and an

oscillator?

2. How can damped oscillations can be converted into undamped oscillations?

3. How are RC oscillators different from LC oscillators?

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Electrical and Electronics Engineering Lab Manual

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Transcript of Electrical and Electronics Engineering Lab Manual