Week 2

Experiment 4: Kirchhoff’s Laws

A.Follow the instructions Steps 1- 16 in Experiment 4: Kirchhoff’s Laws. Note the following modifications: the voltage source is 5 Vand a screen capture of the PSpice simulation should be included as part of the lab report.

Figure 1

B.Complete the following additional instructions:

  1. In the Results worksheet: calculate the percent deviation between the power calculated in the Analysis Steps 4-5 and the power calculated using the measured voltages and currents in Steps 14-15.
  1. In this class we will be using components called potentiometers or trim pots. Trim pots can be used for a number of purposes, but in this lab they will be used as variable resistors.Rebuild the circuit in Figure 1, replacing R1with a 10k trim pot of your choice. Connect the trim pot by wiring pin 1 to node D and pin 2 to node A. Do not wire anything to pin 3.

Figure 2

  1. In the Conclusions worksheet:
  2. What happens to the voltage drop VAB as you turn the knob on the trim pot clockwise? Use KVL to explain your answer.
  3. What happens to the voltage drop VAB as you turn the knob on the trim pot counterclockwise? Use KVL to explain your answer.
  4. What is the function of the trimpot? What parameter is changing when you adjust the knob?

Week 2Pre-Lab Report

Find the report template for Experiment 4, which is linked to Week 2 in the Modules section on the ECE 2074 Scholar site.

  1. Enter the answers from your calculations for Analysis Step 1-6in the appropriate boxes and paste the calculations that you performed in Analysis Steps 1 and 4.on to the Analysis section of the report worksheet in the template for Experiment 4.
  1. Enter the simulation results into the appropriate boxes and paste the screen shot from Modeling Step 8 on to the PSpice worksheet in the template for Experiment 4.

Format for the answers should follow the Guidelines for Formatting Answers, which were posted on the Week 2 module.

Week 2Post-Validation Lab Report

Complete the report template for Experiment 4 with the inclusion of the answers to parts 1 and 3 that were described on the first page of these instructions. Make sure that you include the Analysis and Modeling worksheets that you completed for the Week 2 Pre-Lab Report when you upload your post-validation lab report.

Week 2 Validation

Instructions for the Validation:

Students will have the circuit constructed on the ANDY board, the ANDY board power supply, and the DMM along with their Tablet PC ready for the validation.

Students will have constructed the circuit from Figure 2, where the 8.2 kW resistor has been replaced with a 10 kW trim pot on their ANDY board. This is the circuit shown at the bottom of the first page of this document.

The grade for Week 3 Validation will be based upon two sets of criteria listed below.

Proper Circuit Construction Techniques:

1. Student’s wiring is neat (10%).

2. No wire is more than an inch above the breadboard (10%).

3. A red wire is used for power (10%).

4. A black wire is used for ground (10%).

Proper Measurement Techniques Performed Before an OpEL GTA:

1. Adjust the value of the trim pot such that it is equal to 8.2 k, based upon a measurement of voltage VAB(20%).

2. Measure the voltage VDA(15%).

3. Measure the current IDA(15%).

4. Measure the resistance of the trim pot between pins 1 and 2 (10%).