Purpose:
To apply Kirchoff’s Laws to the analysis of a simple resistive circuit and experimentally verify the laws.
Equipment and Components:
1. Multimeter and Power Supply
2. Resistors: 5.1 kΩ, 13 kΩ, 20 kΩ, 24 kΩ, 43 kΩ, 56 kΩ, 120 kΩ
Note: you may need to use combinations of up to two resisters to create some of the needed values, i.e. for a 20 kΩ use two 10 kΩ in series. Do not worry about getting exact values. Take advantage of the resisters tolerances.
Note that in order to measure current, you must place ammeter in series (before or after) the circuit element.
Procedure:
1.
In Fig. 1, using resistor series/parallel/Δ-Y combinations (see example 3.7 and problem3.52), determine the equivalent resistance seen by the 9 V source as well as the current and power provided to the circuit from the source.
Check: compare the calculated value of current to the simulated value in Lab 1 (.op analysis: current through 5.1k Ω or 43 kΩ resistor). They should match
.
2.
HW 5 Problem: Using node analysis, calculate the voltage drop ( V x
) across the 56 kΩ resistor.
Check: compare the calculated values of node voltages to the simulated values in Lab 1 (.op analysis).
They should match .
3.
HW 7 Problem: Using mesh analysis, calculate currents I
1
and I
2
.
Check: compare the calculated values of currents to the simulated values in Lab 1 (.op analysis). They should match .
4.
Using the node voltages and/or the mesh currents, calculate the power dissipated in each resistor and total power dissipated by the circuit. Will 1/8 W (typical) resistors work for the construction of the circuit?
Fig. 1: Test Circuit

5. Construct the circuit shown in Fig. 1 and perform the following experiments. If the exact resistor values are not available, combine two resistors in series and parallel to obtain the correct nominal value
(you should be able to obtain target values with only two resistors).
6. Remove the power supply and measure the equivalent resistance seen by the power supply with an ohmmeter. Compare the measured value to the calculated value from part1 and explain any discrepancy.
7. Reconnect the power supply and measure the following voltages: Measure V x
and compare it to the calculated value. Measure the voltages for each element in the KVL loop in Fig. 1 and verify that
Kirchhoff’s Voltage Law remains valid. Pay close attention to the polarity of the voltmeter while making these measurements and calculations.
8. Measure the following currents: Measure I
1
and I
2
and compare them to the calculated values.
Measure all currents flowing through the elements connected to node B and verify that Kirchhoff’s
Current Law remains valid. Pay close attention to the polarity of the ammeter while making these measurements and calculations.
9. Measure the current and voltage and calculate the power provided by the 9V power supply. Does this match with the calculated power?
Conclusions:
A good way to write a summary is to create a table with all the values. Compare the circuit measurements with the calculated values and list all values in a table and calculate % errors between the measured vs calculated values (use the following formula). Explain any similarities and discrepancies in these numbers as well as any other measurements conducted during the lab.
Example Table