User:Tyler Wynkoop/Notebook/Junior Lab/Week 1

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Oscilloscope Lab Procedure Notes

SJK 14:48, 24 September 2010 (EDT)
14:48, 24 September 2010 (EDT)
Overall, this primary notebook is a bit thin. Any results that are in your summary would be in your primary notebook. For example, the "extra" work you show in the summary. In good practice, you would have recorded notes about the extra work in your primary notebook, and then summarized them later. In the future, if you're working with Dan, the two of you can share one very good primary notebook and then do analysis and summaries separately.

Procedure Page: Physics307L:Labs/Oscilloscope

Step 1

Set up the Function Generator (FG) and Oscilloscope (Osc) SJK 14:36, 24 September 2010 (EDT)
14:36, 24 September 2010 (EDT)
You are missing the make/model numbers of the equipment. This is essential for good primary notebook. Photos also would help a lot.
  • Tune FG to 200 Hz
  • Use BNC cable [1]

Step 2

Fiddle with Osc and FG settings to get best sine image as follows:

  • 500 Hz
  • DC offset off
  • Output level about one quarter max
  • Trigger at 0; rising
  • Zoom at 1.00V

Step 3

Measuring the sine wave parameters

  • Using the grid lines on the Osc
    • Amplitude approx. 3.61V
    • Period approx. 2.00ms
  • Using cursors
    • Amplitude 3.64V
    • Period 2.000ms
  • Using the measure function
    • Amplitude 3.68V
    • Period 2.000±.004ms

Step 4


  • Triggering (in my own words) is at what voltage, in the sine wave, that the Osc begins to measure the waveform. The Osc must be told first whether to begin measuring the voltage as the wave form rises or falls.

AC/DC Coupling

  • DC coupling allows both DC and AC voltage through to be viewed and measured, AC coupling only allows the AC voltage through. AC coupling can reveal sublties in the voltage that can be masked by DC voltage.

Step 5

  • Fall Time:

Fall time is the characteristic time of the capacitor in the AC coupler in the oscilloscope. It is the time constant (τ) the exponential decay of the voltage across the capacitor represented by the equation:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "":): {\displaystyle V_0 = V_{max}*e^{-t/\tau}}

To find this number, I first changed the FG to display square waves. Secondly, I set the coupling to AC (in order to use the capacitor being measured). Finally, I DC lowered the number of cycles per second (Hz) on the FG to just over 8, to allow the capacitor to fully discharge after each pulse.

  • With cursors, the estimated value is 53.00 ms
  • With the measure function, the value is 55.6±.3ms