LABORATORY MATERIAL
EE0211 – ELECTRICAL CIRCUITS LAB
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING
FACULTY OF ENGINEERING & TECHNOLOGY
SRM UNIVERSITY, Kattankulathur – 603 203
1
CONTENTS
Sl.No.
Name of the Experiments
Page No.
1
Verification of Kirchoff’s laws
3
2
Verification of Superposition theorem
6
3
Verification of Thevenin’s & Norton’s Theorem
9
4
Verification of Maximum Power Transfer theorem
15
5
Power measurement in 3 phase unbalanced circuits
19
6
Power measurement in 3 phase balanced circuits
20
7
Power measurement using 3 voltmeter & 3 ammeter
22
method
8
Circuit analysis using CRO
26
9
Circuit transients by digital simulation
28
10
Study of resonance
30
2
Experiment No. 1
Date :
VERIFICATION OF KIRCHHOFFS LAWS
Aim:
To verify Kirchhoff’s current law and Kirchhoff’s voltage law for the given circuit.
Apparatus Required:
Sl.No.
Apparatus
1
RPS (regulated power supply)
2
Resistance
3
Ammeter
4
Voltmeter
5
Bread Board & Wires
Range
(0-30V)
330, 220 1k
(0-30mA)MC
(0-30V)MC
--
Statement:
KCL: The algebraic sum of the currents meeting at a node is equal to zero.
KVL: In any closed path / mesh, the algebraic sum of all the voltages is zero.
Precautions:
1.
Voltage control knob should be kept at minimum position.
2.
Current control knob of RPS should be kept at maximum position.
Procedure for KCL:
1.
Give the connections as per the circuit diagram.
2.
Set a particular value in RPS.
3.
Note down the corresponding ammeter reading
4.
Repeat the same for different voltages
Procedure for KVL:
1.
Give the connections as per the circuit diagram.
2.
Set a particular value in RPS.
3.
Note all the voltage reading
4.
Repeat the same for different voltages
Circuit - KCL
3
Quantity
2
6
3
3
Required
Circuit - KVL
KCL - Theoretical Values:
Sl.
Voltage
No.
E
Volts
1
5
2
10
3
15
4
20
5
25
KCL - Practical Values:
Sl.
Voltage
No.
E
Volts
1
5
2
15
3
25
KVL – Theoretical Values
Sl.No.
RPS
E1
E2
V
V
1
5
5
2
10
10
3
15
15
4
20
20
5
25
25
I1
mA
5.68
11.3
17.05
22.73
28.42
Current
I2
mA
3.12
6.18
9.37
12.49
15.62
I1
mA
5.6
17.2
28
Current
I2
mA
3.1
9.4
15.6
Voltage
V2
V
4.41
8.83
13.2
17.67
22.08
V1
V
0.58
1.16
1.75
2.33
2.913
4
I1 = I2 + I3
I3
mA
2.56
5.12
7.68
10.24
12.68
mA
5.68
11.3
17.05
22.075
28.42
I1 = I2 + I3
I3
mA
2.2
7.6
12.7
V3
V
0.583
1.17
1.75
2.33
2.915
mA
5.3
17
28.3
KVL
E1 = V1 + V2
V
4.99
9.99
14.95
20
24.993
KVL - Practical Values
Sl.No.
RPS
E1
E2
V
V
1
5
5
2
10
10
3
15
15
Voltage
V2
V
4.4
8.83
13.20
V1
V
0.6
1.13
1.72
V3
V
0.56
1.19
1.78
KVL
E1 = V1 + V2
V
5
9.96
14.92
Model Calculations:
Result:
Thus Kirchoff’s voltage load and Kirchoff’s current law verified both theoretically
and practically.
5
Experiment No. 2
Date :
VERIFICATION OF SUPERPOSITION THEOREM
Aim:
To verify the superposition theorem for the given circuit.
Apparatus Required:
Sl.No.
Apparatus
1
RPS (regulated power supply)
2
Ammeter
3
Resistors
4
Bread Board
5
Wires
Range
(0-30V)
(0-10mA)
1k, 330, 220
---
Quantity
2
1
3
-Required
Statement:
Superposition theorem states that in a linear bilateral network containing more than
one source, the current flowing through the branch is the algebraic sum of the current flowing
through that branch when sources are considered one at a time and replacing other sources by
their respective internal resistances.
Precautions:
1.
2.
Voltage control knob should be kept at manimum position
current control knob of RPS should be kept at maximum position
Procedure:
1.
Give the connections as per the diagram.
2.
Set a particular voltage value using RPS1 and RPS2 & note down the ammeter
reading
3.
Set the same voltage in circuit I using RPS1 alone and short circuit the terminals
and note the ammeter reading.
4.
Set the same voltage in RPS2 alone as in circuit I and note down the ammeter
reading.
5.
Verify superposition theorem.
6
CIRCUIT - 1
CIRCUIT - 2
CIRCUIT - 3
TABULAR COLUMN
Theoretical Values
Circuit – 1
1
10 V
RPS
2
10 V
Ammeter Reading (I)
mA
I = 8.83
Circuit – 2
10 V
0V
I’= 3.5
Circuit – 3
0V
10 V
I”= 5.3
I = I’  I” = 8.83
Practical Values
RPS
Circuit – 1
1
10 V
2
10 V
Ammeter Reading (I)
mA
I = 8.5
Circuit – 2
10 V
0V
I’= 3.5
Circuit – 3
0V
10 V
I”= 5
I = I’  I” = 8.5 mA
= 3.5 + 5 = 8.5 mA
7
Model Calculations:
Result:
Superposition theorem have been verified theoretically and practically.
8
VERIFICATION OF THEVENIN’S THEOREM
Experiment No. 3
Date :
Aim:
To verify Thevenin’s theorem and to find the full load current for the given circuit.
Apparatus Required:
Sl.No.
1
2
3
4
5
Apparatus
RPS (regulated power supply)
Ammeter
Resistors
Bread Board
DRB
Range
(0-30V)
(0-10mA)
1K, 330
---
Quantity
2
1
3,1
Required
1
Statement:
Any linear bilateral, active two terminal network can be replaced by a equivalent
voltage source (VTH). Thevenin’s voltage or VOC in series with looking pack resistance RTH.
Precautions:
1.
Voltage control knob of RPS should be kept at minimum position.
2.
Current control knob of RPS should be kept at maximum position
Procedure:
1.
Connections are given as per the circuit diagram.
2.
Set a particular value of voltage using RPS and note down the corresponding
ammeter readings.
To find VTH
3.
Remove the load resistance and measure the open circuit voltage using multimeter
(VTH).
To find RTH
4.
To find the Thevenin’s resistance, remove the RPS and short circuit it and find the
RTH using multimeter.
5.
Give the connections for equivalent circuit and set VTH and RTH and note the
corresponding ammeter reading.
6.
Verify Thevenins theorem.
Theoretical and Practical Values
E(V)
VTH(V)
RTH()
Theoretical
10
5
495
Practical
10
4.99
484
9
IL (mA)
Circuit - I
Equivalent
Circuit
3.34
3.34
3.3
3.36
Circuit - 1 : To find load current
To find VTH
To find RTH
Thevenin’s Equivalent circuit:
10
Model Calculations:
Result:
Hence the Thevenin’s theorem is verified both practically and theoretically
11
VERIFICATION OF NORTON’S THEOREM
Experiment No. 4
Date :
Aim:
To verify Norton’s theorem for the given circuit.
Apparatus Required:
Sl.No.
1
Ammeter
2
3
4
5
Apparatus
Range
(0-10mA) MC
(0-30mA) MC
330, 1K
(0-30V)
---
Resistors
RPS
Bread Board
Wires
Quantity
1
1
3,1
2
1
Required
Statement:
Any linear, bilateral, active two terminal network can be replaced by an equivalent
current source (IN) in parallel with Norton’s resistance (RN)
Precautions:
1.
Voltage control knob of RPS should be kept at minimum position.
2.
Current control knob of RPS should be kept at maximum position.
Procedure:
1.
Connections are given as per circuit diagram.
2.
Set a particular value in RPS and note down the ammeter readings in the original
circuit.
To Find IN:
3.
Remove the load resistance and short circuit the terminals.
4.
For the same RPS voltage note down the ammeter readings.
To Find RN:
5.
Remove RPS and short circuit the terminal and remove the load and note down
the resistance across the two terminals.
Equivalent Circuit:
6.
Set IN and RN and note down the ammeter readings.
7.
Verify Norton’s theorem.
12
To find load current in circuit 1:
To find IN
To find RN
Norton’s equivalent circuit
Constant current source
13
Theoretical and Practical Values
E
IN
(volts)
(mA)
RN
()
IL (mA)
Circuit - I
Theoretical
Values
Practical
Values
10
10.10
495
334
Equivalent
Circuit
3.34
10
10.4
485
3.4
4
Model Calculations:
Result:
Norton’s was verified practically and theoretically
14
Experiment No. 5
Date :
VERIFICATION OF MAXIMUM POWER TRANSFER
THEOREM
Aim:
To verify maximum power transfer theorem for the given circuit
Apparatus Required:
Sl.No.
1
2
3
4
5
Apparatus
Range
(0-30V)
(0-10V) MC
1K, 1.3K, 3
---
RPS
Voltmeter
Resistor
DRB
Bread Board & wires
Quantity
1
1
3
1
Required
Statement:
In a linear, bilateral circuit the maximum power will be transferred to the load when
load resistance is equal to source resistance.
Precautions:
1.
Voltage control knob of RPS should be kept at minimum position.
2.
Current control knob of RPS should be kept at maximum position.
Procedure:
Circuit – I
1.
Connections are given as per the diagram and set a particular voltage in RPS.
2.
Vary RL and note down the corresponding ammeter and voltmeter reading.
3.
Repeat the procedure for different values of RL & Tabulate it.
4.
Calculate the power for each value of RL.
To find VTH:
5.
Remove the load, and determine the open circuit voltage using multimeter (VTH)
To find RTH:
6.
Remove the load and short circuit the voltage source (RPS).
7.
Find the looking back resistance (RTH) using multimeter.
Equivalent Circuit:
8.
Set VTH using RPS and RTH using DRB and note down the ammeter reading.
9.
Calculate the power delivered to the load (RL = RTH)
10.
Verify maximum transfer theorem.
15
Circuit - 1
To find VTH
To find RTH
Thevenin’s Equation Circuit
16
Power VS RL
Circuit – I
Sl.No.
1
RL ()
200
I (mA)
1.3
V(V)
0.27
P=VI (watts)
0.26
2
400
1.2
0.481
0.53
3
600
1.1
0.638
0.707
4
800
1
0.771
0.771
5
1200
0.80
1.083
0.866
6
1300
0.77
1.024
0.788
7
1400
0.74
0.998
0.738
8
1500
0.71
0.968
0.687
RTH ()
1320
IL (mA)
0.758
P (milli watts)
0.759
1306
0.77
0.77
To find Thevenin’s equivalent circuit
VTH (V)
2002
Theoretical
Value
2
Practical Value
17
Model Calculations:
Result:
Thus maximum power theorem was verified both practically and theoretically
18
Experiment No. 6
Date :
THREE PHASE POWER MEASUREMENT
(TWO WATTMETER METHOD)
Aim:
To measure the 3-phase active and reactive power by 2 – wattmeter method for (i)
resistance load (ii) inductive load
Apparatus Required:
Sl.No.
1
2
3
4
Apparatus
Range
(0-600V) MI
(0-20A) MI
600V, 10A, UPF
600V, 10A, LPF
Voltmeter
Ammeter
Wattmeter
Wattmeter
Precautions:
 THE TPST switch must be kept open initially.
 Load must not be applied while starting.
Procedure:
(i) – Resistive load
1.
2.
3.
Give the connections as per the circuit diagram.
Give the supply by closing TPST switch.
Vary the resistance load and note down the corresponding readings.
(ii) Inductive load
1.
Give the connections as per the circuit diagram.
2.
Give the supply by closing the TPST switch
3.
Vary the inductive load and note down the corresponding readings.
for inductive load
19
Quantity
1
1
2
2
for resistive load
Formulae Used:
1.
Real power = w1 + w2
2.
Reactive power =
3.
Tan  =
4.
Power factor = cos 
3 (w1  w2 )
3 ( w1  w2 )
w1  w2
Two Wattmeter Method : Resistive Load
V
(volt)
460
460
460
460
460
460
460
460
460
I
(A)
0
1.8
3.7
4.6
5.5
6.3
7.2
8.1
9
MF =
Wattmeter
Reading (W1)
OBS
ACT =
(watt) OBS X
MF
(watt)
0
0
70
560
160
1280
200
1600
240
1920
280
2240
320
2560
350
2800
390
3120
MF =
Wattmeter
Reading (W2)
OBS
ACT=OBS
(watt)
x MF
(watt)
0
90
180
210
250
290
330
370
410
20
0
720
1440
1680
2000
2320
2640
2960
3280
Power
Cos 
Real
Power
(watt)
Reactive
power
(watt)
0
1280
2720
3280
3920
4560
5200
5760
6400
0
-277.12
-277.12
-138.56
-138.56
-138.56
-138.56
-277.12
-277.12
0
0.977
0.9949
0.999
0.9
0.993
0.996
0.9988
0.990
Two Wattmeter Method : Inductive Load
V
(volt)
I
(A)
410
410
410
410
410
410
1
2
3
4
5
6
MF =
Wattmeter
Reading (W1)
OBS
ACT =
(watt) OBS x
MF
(watt)
11
89
15
120
28
140
43
344
78
624
95
760
MF =
Wattmeter
Reading (W2)
OBS
ACT=OBS
(watt)
x MF
(watt)
26
32
53
80
106
132
208
256
424
640
848
1056
Power
Cos 
Real
Power
(watt)
Reactive
power
(watt)
296
376
564
984
1472
1816
-554.26
-443.41
-734.39
-1108.51
-1461.78
-1829.05
0.351
0.647
0.609
0.664
0.708
0.705
Model Calculations:
Result:
Thus power for three phase power supply was measured using 2 wattmeter method.
21
Experiment No. 7
Date :
POWER MEASUREMENT BY 3 - VOLTMETER
Aim:
To measure the power in an inductive circuit, Eg: transformer, by 3- voltmeter
method.
Apparatus Required:
Sl.No.
1
Ammeter
2
Voltmeter
3
4
5
6
Apparatus
Range
(0-5A) MI
(0-150V) MI
(0-300V) MI
230V/115V, 1KVA
100
Transformer
Auto Transformer
Auto Transformer
Rheostat
Quantity
1
2
1
1
1
1
Precaution:
1.
The DPST switch must be kept open initially.
2.
The auto transformer must be kept at minimum potential position
3.
The rheostat must be kept at maximum resistance position.
Procedure:
1.
Give the connections as per the circuit diagram.
2.
Adjust the auto transformer, to bring the rated voltage of the transformer
3.
Note down the transformer and voltmeter readings.
4.
Vary the rheostat for different values and note down the corresponding meter
readings.
3 – Voltmeter Method
Sl.
I
No.
(amp)
1
0.2
2
0.6
3
0.8
4
1
5
1.1
6
1.2
Vs
(volts)
150
150
150
150
150
150
VR
(volts)
15
54
73
86
90
95
VL
(volts)
136
120
120
110
105
100
22
P
(watts)
25.193
21.99
15.18
17.46
20.625
21.99
Cos 
0.82
0.293
0.158
0.158
0.178
0.182
Formulae Used:
1.
Power (P) =
VS2  VR2  VL2
watts
2R
R = VR / I
2.
VS2  VR2  VL2
Cos  =
2 Ve VL
Model Calculations:
Result:
The power was measured for given circuit using 3 voltmeter method
23
Experiment No. 8
Date :
POWER MEASUREMENT BY 3 - AMMETER
Aim:
To measure the power in an inductive circuit, Eg: transformer, by 3- ammeter method.
Apparatus Required:
Sl.No.
1
Ammeter
Apparatus
2
3
4
Voltmeter
Auto transformer
Transformer
5
Rheostat
Range
(0-2A) MI
(0-5A) MI
(0-150V) MI
230V/115V
1KVA, 1
100 / 4A
Quantity
2
1
1
1
1
1
Precaution
1.
The DPST switch must be kept open initially
2.
The autotransformer should be kept at minimum potential position
3.
The rheostat should be kept at maximum resistance position
Procedure:
1.
Give the connections as per the circuit diagram
2.
Adjust the auto transformer, to bring the rated voltage of the transformer
3.
Note down the ammeter and voltmeter readings.
4.
Vary the rheostat for different values and note
3 – Voltmeter Method
Sl.
No.
1
2
6
4
5
6
V
(volts)
115
115
115
115
115
115
Is
(amp)
0.75
0.85
0.95
1.05
1.15
1.25
IR
(amp)
0.54
0.6
0.7
0.8
0.9
1
IL
(amp)
0.48
0.48
0.48
0.48
0.48
0.46
24
R
(ohm)
213
191.67
164.3
143.7
127.7
0.46
P
(watts)
4.31
912.6
14.9
16.6
18
20.1
Cos 
0.07
0.22
0.57
0.3
0.32
0.37
Formulae Used:
Power (P) = R
2
I
2
S
 I R2  I L2

R = V / IR
Power factor cos  =
I S2  I R2  I L2
2 IR IL
Model Calculations:
Result:
Thus power was measured using 3 ammeter method
25
Experiment No. 9
Date :
CIRCUIT ANALYSIS USING CRO
Aim:
To measure voltage and current and also to study the phase relationship between
supply voltage and current in series RC circuit.
Apparatus Required:
Sl.No.
1
2
3
4
5
Apparatus
Function generator
DMM
Resistor
Capacitor
CRO
Range
200 
1 F
Quantity
1
1
1
1
1
Procedure:
1.
Connections are given as per the circuit diagram.
2.
In the function generator, select “SINE WAVE” as the output and set the
frequency to 200 Hz.
3.
Adjust the amplitude knob of the function generator until the waveform on the
oscilloscope shows 2 Vp.
4.
Record the peak voltage across the resistor using CRO.
5.
Calculate  from t.
6.
Draw the waveform for VS, VR.
Circuit Diagram:
26
Sl.No.
1
Sl.No.
1
Frequency
(Hz)
200
VR
V
0.4
T
(ms)
5
t
(ms)
0.3

deg
21.6
(leading
Frequency
(Hz)
0.32
VR
V
1.6mA
T
(ms)
1.2
t
(ms)
750

deg
7.95
Result:
The phase relationship between supply voltage and current in series RC circuit is
studied and also the voltage and current are increased practically.
27
Experiment No. 10
Date :
CIRCUIT TRANSIENTS BY SIMULATION IN RL
CIRCUIT
Aim:
To simulate the RL circuit using Pspice software and to study the transient response
Circuit Diagram:
Simulation Parameter:
Vdc = 10 volts, R1 = 50 ohms, L = 100mH
28
Simulation Output:
1.
Transient L wave form
2.
Transient R wave form
Result:
Simulation of the RL transient circuit was done
29
Experiment No. 11
Date :
STUDY OF RESOURCE
Aim:
To study series and parallel resource in AC circuit
Series Resource:
An RLC circuit is said to be at re source when voltage and current are in phase with
each other and power factor is unity.
Z  R  j( X L  X C ) z
At series resource
XL = XC
Z=R
XL = XC
1
L 
C
2 
1
LC
(2 n fr ) 2 
fr 
Power factor cos  
Q - factor =
1
LC
1
2 LC
R
Z
VC VL

V
V
Parallel Resonance:
Parallel AC circuit is said to be at resource when voltage and current are in phase with
each other and power factor is unity.
(i)
ideal parallel circuit f 0 
(ii)
Practical circuit - I f 0 
(iii)
Practical circuit – II f 0 
1
2 u LC
1
2u
1 R2

LC L2
1
2u
 (R ) 2  L / C
L

2

(
R
IC 
L)  L/C
30



