DE LA SALLE LIPA
COLLEGE OF INFORMATION TECHNOLOGY AND ENGINEERING
ELECTRICAL ENGINEERING DEPARTMENT
EXPERIMENT NO. 7
SUPERPOSITION THEOREM
SUBMITTED BY:
HORSTMAN, CHARLON
LINGAO, AIRA SHAYNE
RAZO, MA. EUNICE
SUBMITTED TO:
Engr. RODELIO H. CABRERA
DE LA SALLE LIPA
COLLEGE OF INFORMATION TECHNOLOGY AND ENGINEERING
ELECTRICAL ENGINEERING DEPARTMENT
EXPERIMENT #7: SUPERPOSITION THEOREM
I. OBJECTIVE
To study and apply the superposition theorem in the solution of an electric
network
II. DISCUSSION
The superposition may be stated as follows:
The current which follows at any point in the network involving
more than one source may be considered to be algebraic sum of the
currents which flow as a result of each source taken separately.
Consider the circuit shown in Fig. 7.1. to apply the superposition
theorem to such a circuit, we first replace the EB source with a short
circuit as shown in Fig. 7.2a. I1A, I2A, and I3A are computed using Ohm’s
law. Then we return source EB and remove source EA, replacing it with
a short circuit. I1B, I2B, and I3B are then determined using the Ohm’s law.
We may now combine the results of the two sets of calculations to
find the currents I1, I2, and I3 in Fig. 7.1. We observe in this case that
I1A and I1B oppose each other, as do I2A and I2B. On the other hand I3A
and I3B reinforce each other. Consequently, we have:
I1 = I1A – I1B , I2 = I2A – I2B , and I3 = I3A + I3B
The directions in which I1, I2, and I3 will flow are determined by
the directions of the components current. That is in the case of I1, the
direction will be the same as the larger of I1A and I1B. The same is true
of I2 with respect to I2A and I2B. For I3, it will be in the same direction as
I3A or I3B.
III. INSTRUMENTS AND COMPONENTS
ITEM NO. DESCRIPTION QUANTITY
Feedback Trainer 1
Multimeter 2
1000 ohm resistor 1
680 ohm resistor 1
470 ohm resistor 1
330 ohm resistor 1
220 ohm resistor 1
100 ohm resistor 1
2
DE LA SALLE LIPA
COLLEGE OF INFORMATION TECHNOLOGY AND ENGINEERING
ELECTRICAL ENGINEERING DEPARTMENT
IV. PROCEDURE
1. Connect the circuit shown in Fig. 7.1. The values of the resistors and voltages of
the sources will be assigned by your instructor.
2. Measure and record each of the currents I1, I2, and I3.
3. Disconnect the EB source and place a short circuit across the network between
points B and B’.
4. Measure and record the currents I1A, I2A, and I3A
5. Remove the short circuit and reconnect the EB source and place a short circuit
across the network between points A and A’.
6. Measure and record the currents I1B, I2B, and I3B.
7. Compute I1’, I2’, and I3’ using the measured component currents.
8. Compute the percent difference between each of the pairs of values of I1, I2, and
I3.
V. CIRCUIT DIAGRAM
3
DE LA SALLE LIPA
COLLEGE OF INFORMATION TECHNOLOGY AND ENGINEERING
ELECTRICAL ENGINEERING DEPARTMENT
4
DE LA SALLE LIPA
COLLEGE OF INFORMATION TECHNOLOGY AND ENGINEERING
ELECTRICAL ENGINEERING DEPARTMENT
VI. DATA AND RESULTS
I1 I2 I3 I1A I2A I3A I1B I2B I3B I1’ I2’ I3’
6.2 2.2 8.4 0.4 1.8 7.8 6.4 0.6 0.6 6.8 2.4 8.4
mA mA mA mA mA mA mA mA mA mA mA mA
Percent difference between I1 and I1’ = 9.68 %
Percent difference between I2 and I2’ = 9.09 %
Percent difference between I3 and I3’= 0%
VII. PROBLEMS
1. If the superposition theorem is used to solve an electric network, how do you
determine the actual direction of the currents?
In using superposition theorem, you are acquiring current values with respect to
your assumed current direction called the branch current. It is being solve separately
according to the acting alone independent voltage or current sources. If your computed
current values are at positive, then your assumed current direction is correct. On the
contrary, negative current values are at opposite direction.
2. Apply superposition to the circuit of figure shown to find I1, I2 and I3.
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DE LA SALLE LIPA
COLLEGE OF INFORMATION TECHNOLOGY AND ENGINEERING
ELECTRICAL ENGINEERING DEPARTMENT
6
DE LA SALLE LIPA
COLLEGE OF INFORMATION TECHNOLOGY AND ENGINEERING
ELECTRICAL ENGINEERING DEPARTMENT
VIII. CONCLUSION
In superposition theorem, the total current entering a load from combined
E.M.F. sources equals the algebraic sum of individual caused by E.M.F. sources
acting alone. It is required to use superposition theorem only when the
independent sources in a circuit are fundamentally different. It is not
recommended to use this theorem in a simple circuit which can be easily solve
by mesh analysis, nodal analysis and other different methods. Compare to the
other methods, Superposition theorem is more difficult, because the more the
independent voltage or current source the more the condition which are required
to solve multiple times.
