Capitol College
Spring Semester 2000
Lab Experiment #3
Andy Buettner
Instructor: Dr. Thomas
Due: March 21^{st}, 2000
Received: ___________________
Objective
The objective of this lab is to determine the currents in a circuit with multiple sources using mesh analysis. Then, use mesh analysis to analyze a complex circuit. Lastly to compare the results with experimentally determined values.
Equipment Used
Equipment used
ET  3100 Trainer #1517
Fluke DMM ser. no: 31101554
Lab kit EE  159
Components used
470 Ohm Resistor
680 Ohm Resistor
330 Ohm Resistor
1K Ohm Resistor
220 Ohm Resistor
Procedures
1) Measure and record the individual resistances of each resistor
2) Assemble circuit from Diagram 1
3) Set voltages for both sides of the source
4) Measure voltages across each resistor
1) Measure the individual resistances of the resistors
2) Assemble the circuit in diagram 2
3) Set voltage on Trainer to 10 volts
4) Measure the voltages across each resistor
Results
Table 1

R_{1} 
R_{2} 
R_{3} 
R_{4} 
Measured Resistance 
459 W 
670 W 
329 W 
990 W 
Measured Voltage 
1.838V 
2.685V 
.510V 
5.47V 
Calculated Current 
4.004ma 
4.007ma 
1.550ma 
5.525ma 
Determined Current 
3.994ma 
3.994ma 
1.551ma 
5.545ma 
Table 2

R_{1} 
R_{2} 
R_{3} 
R_{4} 
R_{5} 
Measured Resistance 
459 W 
670 W 
329 W 
990 W 
218 W 
Measured Voltage 
6.16V 
2.960V 
3.483V 
6.48V 
3.811V 
Calculated Current 
13.42ma 
4.418ma 
10.59ma 
6.545ma 
17.48ma 
Determined Current 
13.47ma 
4.03ma 
10.61ma 
6.58ma 
17.50ma 
Diagram 1
Diagram 2
Answers to Lab Questions
Q: Calculate the currents through each resistor using mesh analysis.
A: Answers in tables 1 & 2.
2) Q: Calculate the currents through each resistor using Ohm's law.
A: Answers in Tables 1 & 2.
3) Q: Compare results.
A: The results are nearly identical and in some cases are.
4) Q: Explain how a negative voltage can be made to be positive.
A: Reverse the poles of the volt  meter.
5) Q: The trainer can only produce differences of 15V. How can a difference of 30V be obtained?
A: By using both the positive and negative terminals instead of the ground terminal.
6) Q: What does the DMM read when the battery is low?
A: There is an icon in the top center that shows a battery with an X through it.
Conclusions
In order to complete this lab I used several aids to help me. First, to completely analyze the mesh analysis, I used my equationsolving program to perform the matrix math. Also, I used the found values of the resistors instead of the read ones to complete the mesh analysis. I found it interesting to find out exactly how little error was involved in this exercise.
Attachments
Original Handout
Original Data
Calculations