Network Analysis
Class/Branch: S.E. Electrical
Experiment Number: 01
Title:
Verification of Superposition theorem for A.C. circuits
Aim:
To verify Superposition theorem for A.C. circuits
Apparatus:
1.
2.
3.
4.
5.
6.
7.
Medium transmission line ‘T’ model
AC Power Supply
AC Voltmeter (0 - 150 V)
AC Ammeter (0 - 1 A)
Multimeter (Optional)
Single Phase Autotransformer
Connecting wires
Diagram:
4
ohm
110
mH
V1
Theory:
4
ohm
0.47
micro
farad
110
mH
V2
Statement of Superposition theorem:
“Superposition theorem states that “In a linear network containing more
than one independent source & dependent sources, the resultant current in
any element is the algebraic sum of the currents that would be produced by
each independent source acting alone, all the other independent sources
being represented meanwhile by their respective internal resistances.”
The independent voltage sources are represented by their internal resistance if
given or simply with zero resistance, i.e. short circuits if internal resistances are
not mentioned. The independent current sources are represented by infinite
resistance, i.e. open circuit.
Suppose, we have to apply Superposition theorem to following circuit then,
Department of Electrical Engineering
ZES’s ZCOER, Pune-411041
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Network Analysis
Class/Branch: S.E. Electrical
From the above circuit we have to determine the total currents due to effect of
only one source at a time. Both the sources given in the above network have
control variable V and I but it is to be noted that V and I does not make the source
dependent on the variable of any portion of the network shown above.
Steps to be followed for superposition theorem.
1. First find current through ZB by removing i.e. opening current source. This
current is due to voltage source only.
𝐼′ =
𝛼. 𝑉
𝑍𝐴 + 𝑍𝐵
2. Next, the voltage source being removed (i.e. voltage source is short
circuited) and current through ZB is found.
𝐼 ′′ =
Department of Electrical Engineering
ZES’s ZCOER, Pune-411041
𝑍𝐴
. 𝛽𝐼
𝑍𝐴 + 𝑍𝐵
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Network Analysis
Class/Branch: S.E. Electrical
3. The resultant current by using superposition theorem is
𝐼 = 𝐼 ′ + 𝐼 ′′
Procedure:
1. Connections are made as per the circuit diagram
2. The readings of voltmeter and ammeter are noted with one source
at a time.
3. After connecting both sources, the voltmeter and ammeter
readings are noted.
4. The procedure is repeated for different values of source voltage
5. Observed readings and calculated readings are compared to verify
superposition theorem.
Observation
table:
IRL1
Observed
Values
Calculated
values
IRL2
Observed
Values
Calculated
Values
With V1
With V2
Both V1 & V2
Calculations: Do the calculation on Blank ruled pages.
Conclusion:
=======================================================
Department of Electrical Engineering
ZES’s ZCOER, Pune-411041
Page 3