Physics307L F07:People/Knockel/Notebook/070829
Oscilloscope lab
Basic Waveform Measurement
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So I hooked up the oscilloscope to the function generator with a coaxial cable into channel 1 and 2 of the oscilloscope. Both cables carried the same signal. The type of connectors used were BNC. I almost understand the function generator thanks to Lorenzo and Koch, and I get the screen on the oscilloscope to create some cool periodic functions.
I created a sine pulse with the function generator at 200 Hz at about medium amplitude. The oscilloscope measured it to be 196 Hz and to have an amplitude of about 7 V. Changing the shape from a sine to different jagged periodic function didn't change the amplitude or frequency measured by the oscilloscope. Very low frequencies could be measured (down to .1 Hz), but high frequencies, once I zoomed in enough, created a jittery fuzzy curve. The stepwise function at high frequencies didn't create sharp bends. Maybe the crappy wire setup I had caused this. Also, at high amplitude, DC offset did not work in its full range because the function generator was maxing out.
Triggering
Triggering is how you can have the waveform on the screen of the oscilloscope always start at the same stage in the waveform's period. Triggering on a rising edge means that the waveform will always have a positive slope where the arrow on the top of the screen is.
AC coupling
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I generated a square/stepwise wave at 8.6 V amplitude. Relax time (the time it takes for the V measured by the oscilloscope to go to %10) was measured as:
- 52ms
- 53ms
- 52ms
These measurements imply the following RC constants ([math]\displaystyle{ RC=\tau=\frac {t_r}{2.197} }[/math]):
- 23.7ms
- 24.1ms
- 23.7ms
I don't know if I should expect these values on my oscilloscope because I am no longer sitting in front of it.