Monday, February 6, 2017

Week 5

1. Functional check: Oscilloscope manual page 5. Perform the functional check (photo).

Figure 1: Picture displaying function check on oscilloscope
  • The function check was obtained on the oscilloscope by connecting the probe to the 5v output on the device and the ground clip to the ground.

2. Perform manual probe compensation (Oscilloscope manual page 8) (Photo of overcompensation and proper compensation).

Figure 2: Proper compensation
  • Our probe was already calibrated when we got it so it did not require any compensation.

3. What does probe attenuation (1x vs 10x) do (Oscilloscope manual page 9)?

  • Probe attenuation controls the bandwidth of the oscilloscope. 10x uses full bandwidth while 1x is limited to 7MHz. While in 10x the amplitude of the signal will be reduced to a 10th of 1.

4. How do vertical and horizontal controls work? Why would you need it (Oscilloscope manual pages 34-35)?

  • The vertical controls the vertical axis(voltage) and the horizontal controls the horizontal axis(time).The controls work by translating the wave either vertically or horizontally, vertically for amplitude while horizontally is for frequency. You would need this to be able to see more or less of the wave.

5. Generate a 1 kHz, 0.5 Vpp around a DC 1 V from the function generator (use the output connector). DO NOT USE oscilloscope probes for the function generator. There is a separate BNC cable for the function generator.

a) Connect this to the oscilloscope and verify the input signal using the horizontal and vertical readings (photo).
Figure 3: The picture above shows the oscilloscope at 1Khz and 0.5Vpp.

b) Figure out how to measure the signal properties using menu buttons on the scope.
Figure 4: Video shows how to measure the signal properties using menu buttons.

6. Connect function generator and oscilloscope probes switched (red to black, black to red). What happens? Why?

  • No signal is shown because when reversing the connection the output of the oscilloscope is grounded and completely negated.

7.  After calibrating the second probe, implement the voltage divider current below. Measure the following voltages using the Oscilloscope and comment on your results:


Figure 5: picture depiction of the circuit being measured
a. Va and Vb at the same time (Photo)
Figure 6: Picture of the waves from the circuit above

b. Voltage across R4

  • The voltage across R4 is equal to the voltage of every other resistor in the same circuit.The value we got for Vpp was 0.75V.
8. For the same circuit above, measure Va and Vb using the handheld DMM both in AC and DC mode. What are your findings? Explain.

  • In the table below we took note on the measurements that were acquired using the circuit presented on problem seven. We used handheld DMM, and we measured in both AC and DC. We found out that the voltage for Vb is exactly double the measure of Va.

Figure 7: Table of voltages obtained from the circuit
9. For the circuit below

a. Calculate R so given voltage values are satisfied. Explain your work (video)

Figure 8: Video explaining the calculations for R

b. Construct the circuit and measure the values with the DMM and oscilloscope (video). Hint: 1kΩ cannot be probed directly by the scope. But R6 and R7 are in series and it does not matter which one is connected to the function generator.
Figure 9: Video of voltages being measured.

Figure 10: Picture depiction of circuit in videos.

10. Operational amplifier basics: Construct the following circuits using the pin diagram of the opamp. The half circle on top of the pin diagram corresponds to the notch on the integrated circuit (IC). Explanations of the pin numbers are below:

Figure 11: Picture depiction of amplifier and pin diagram.

a. Inverting amplifier: Rin = 1kΩ, Rf = 5kΩ (do not forget -10 V and +10 V). Apply 1 Vpp @ 1kHz. Observe input and output at the same time. What happens if you slowly increase the input voltage up to 5 V? Explain your findings. (Video)

Figure 12: Video displaying inverting amplifier circuit

b. Non-inverting amplifier: R1 = 1kΩ, R2 = 5kΩ (do not forget -10 V and +10 V). Apply 1 Vpp @ 1kHz. Observe input and output at the same time. What happens if you slowly increase the input voltage up to 5 V? Explain your findings. (Video)

Figure 13: Video displaying non-inverting amplifier circuit.


  1. Your #5 input signal looks good, after looking at your photo. I think our input signal was incorrect because we a DC input voltage. Now I see that we should have had an AC input voltage from our function generator.

    1. thank you for the feedback. Im not sure about number 5, i found it confusing mixing ac with dc input

  2. Your #5 also seems to have a low input voltage (26.2mV pp). I would have thought that you would get about .5 V pp. I am unsure though seeing as I could only get a DC signal on my experiment.

    1. Thank you for the feedback. I found number 5 to be somewhat difficult as mixing dc and ac seemed to cause room for error. Im really not sure if our was right or wrong but i think we may have grounded it improperly causing a error with the measurement.

  3. For #6 I think the output of the scope is grounded not the function generator, and the output of the function generator is going to short it

    1. Looking back on it i think you're right. Thank you for the feedback!

  4. You guys have a good blog. You just have to finish up the videos and the resistor calculation on 9. I like that some of your photos have captions under them, but it would be nice if you kept that consistent. And all of your numbers are about the same that my group got, so good job!

    1. Thank you for the feedback! its comforting to know others got numbers near ours so we must be doing something correct.

  5. For number 7 it seems that you measured the voltage drop across each of the resistors, and therefore got the same value for each measurement. What my group did was measured Va and Vb with respect to ground, and the voltage drop across R4. I am not sure which was the right way, but your findings from these measurements are also consistent with theory.

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  7. For question #2 I don't see the photo of overcompensation in there. I only see the photo of proper compensation. There is a big difference between our photos for question #5. We did get a totally different shape. I tried to look though it and see what is wrong with it, but I just couldn't figure it out, but I think yours is right. I liked how you did the video to explain your calculations.
    Well done.