E11 Lab 1 Report

This lab does not have a formal report, you should simply turn in the information requested.  Include a title page with title of lab, the names of people in your group, the day the lab was performed, and the day you turned in the lab.  You should feel free to include handwritten sections if it is quicker than formatting equations, or making computer drawings...

If you are having a lot of trouble with part of the report, please come see me.  I don't want the writing of the lab report to be an exercise in frustration, so if you get stuck, please don't hesitate to ask for help.  Also, if you find you are missing some data, or it just doesn't make sense, please talk to me before finishing your report.

1) Verification of ohms law (part 1 of lab):

  1. Use Matlab to plot V vs I for the 10k Ohm resistor. Include a best fit straight-line for the data as calculated by Matlab (Simple curve fitting with Matalb).  The slope of the graph, I/V, will give the inverse of resistance.  Print out both the spreadsheet and the graphs in your report. Make sure that you show both your experimental and your best fit line on the same graph for easy comparison.   Make sure the axes of your graph are clearly marked, including labels, scales, and units.
  2. Repeat the above procedure for the 20k Ohm resistor
  3. Compare the measured values for resistance with the given value of the resistor.  The resistors have a 5% tolerance (they are supposed to be within 5% of the nominal value).  Is this consistent with your results?

2) Use Matlab to plot one cycle of a cosine wave (part 3 of lab):

  1. Very briefly (one or two sentences each) describe what each line of the Matlab code does in Matlab code section 1 and Matlab code section 2.
  2. Use Matlab to plot just one cycle of a cosine wave from the data recorded from the oscilloscope.  Make your plot begin at t=0 at the beginning of the sine wave (remember a cosine wave is at a maximum at t=0).  You will have to extract one oscillation of the wave (starting at a maximum), and then reset the time vector so it starts at 0 at the beginning of the oscillation.  The easiest way to do this is to use Matlab's array editor to select the appropriate values from the "data" array (double click on the variable in the "Workspace" window).  It can also be done with the "find" command.  I can help you with either one if you have trouble.  Label the plot and the axes.

3) Voltage, Current, Ammeters and Voltmeters

Answer the following briefly, at most one or two sentences for each.

  1. If the voltmeter is to give an accurate reading of a voltage without affecting the circuit being measured, does it behave as an open circuit, or a short circuit?  Explain.
  2. If the ammeter is to give an accurate reading of current without effecting the circuit being measured, does it behave as an open circuit, or a short circuit?  Explain.
  3. Redraw the circuit shown with an ammeter and a voltmeter included such that the current through R1 and the voltage across R2 are being measured.  What reading would you expect from each meter?

  4. Repeat (c) but measure the total current through both R1 and R2 combined, and the battery voltage.  What reading would you expect from each meter?

  5. Briefly explain the difference between voltage and current.

4) The Function Generator and oscilloscope: 
Answer the following briefly, one sentence for each.  The voltage and time scales are the same for all of the images shown below.  The trigger occurs in the middle of the screen.

  1. Consider Images IIa1 and IIa2.  If you know that only an adjustment to the function generator was made, what was that adjustment?
    Image IIa1
    Image IIa2


  2. Consider Images IIa1 and IIa2.  If you know that the only difference has to do with the coupling mode of the oscilloscope, which mode is active in each image?
  3. Consider Images IIc1 and IIc2..  What single adjustment to the triggering of the oscilloscope would go from one to the other?
    Image IIc1
    Image IIc2


  4. Consider Image IId1 and Image IId2.  What single adjustment to the triggering of the oscilloscope would go from one to the other?
    Image IId1
    Image IId2

5) Besting the Professional Engineers

Read my page describing a solution to a design problem.

  1. Show your well documented Matlab script that solves the problem (i.e., finds R1, R2, R3) for the case

  2. Show your circuit in MultiSim along with the results of a simulation that verifies your solution.  Make sure you label the input and output voltages.

  3. (Note: Part c is optional and is worth an extra 5 points (out of 100).) 
    Solve the two cases below for R1, R2 and R3 (no MultiSim needed).  Clearly explain difficulties (if any) that you might have if you tried to implement the solutions.

    Case 1

    Case 2

    • Vin,min=0
    • Vin,max=5
    • VAD,min=0
    • VAD,max=2.5
    • Vdd=5
    • Vss=0
    • RThevenin=5000
    • Vin,min=-5
    • Vin,max=5
    • VAD,min=0
    • VAD,max=10
    • Vdd=5
    • Vss=0
    • RThevenin=5000

Here is a link to the grading sheet I will use, so you can see how much each part of the lab is worth.

You may use any portion of this document for your lab report, but be sure to reference it.

Foxtrot 1

email me with any comments on how to improve the information on this page (either presentation or content), or to let me know if you had any particular difficulties with this lab.