UNIVERSITY OF MASSACHUSETTS DARTMOUTH
DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING
ECE 201
CIRCUIT THEORY I
SUPERPOSITION
BACKGROUND
The principle of Superposition states that the total response of a linear circuit excited by more
than one independent source can be represented as the algebraic sum of the responses to each
source applied individually. In this experiment, you will determine the voltage across and the
current through a resistor in a circuit that is excited by two independent voltage sources by
measuring the contribution from each source acting individually and the total response due to
both sources.
PRELIMINARY WORK / PRELAB
Determine the voltage across and the current through the 100Ω resistor in the circuit shown in
Figure 1 by using Superposition. Perform all of the calculations and create a table of the
expected results in your lab notebook. Your table should include the results due to each source
individually as well as the results due to both sources simultaneously.
Run a Multisim simulation to verify the expected values of the voltage and current.
Hand in a copy of both your solution and the Multisim simulation to the instructor or TA for their
approval before the lab session starts.
R3Voltage
+
0.000 V
DC 1MOhm
R1
R3
470 Ohm
100 Ohm
R3Current
0.000 A
R5
+
220 Ohm
DC 1e-009Ohm
V1
12 V
R2
560 Ohm
R4
330 Ohm
Figure 1. A linear circuit excited with two voltage sources.
V2
6V
PROCEDURE/RESULTS
Construct the circuit in Figure 1 on your breadboard, making sure to provide a method for easy
connection of the measurement instruments. In your lab notebook, prepare a table to record the
values of the voltage across and the current through the 100Ω resistor that you measure with
your ammeter and voltmeter under the following conditions:
a) applying the 12V source only
b) applying the 6V source only
c) applying both sources
How do your measured values compare with the expected results determined in the Preliminary
Work?
2