User:Corbin A. Plugge/Notebook/Physics307L/2010/09/01

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Oscilloscope lab day 2

Equipment

  • Tektronix TDS1002 Digital oscilloscope
  • bk precision 4017A 10MHz sweep/function generator

Setup

  • Function generator output was connected to the oscilloscope ch1 input via a BNC cable.
  • Both devices were plugged into a 115V power strip.

Triggering

  • Edge trigger was the only trigger that I was able to make use of.
  • The trigger could be set for rising or falling edge and adjusted to a specified amplitude.
  • By adjusting the amplitude of the trigger I found I could effectively move the plot left and right. This was helpful in making measurement using the grid.

AC coupling

  • Switching to AC coupling removed the DC offset making waves with a DC offset easier to view.
  • As a side note I observed that the peaks of the waves flattened out when I gave the signal a large DC offset.

measuring Fall time: with a square wave

Thanks to Katie Richardson for her help with understanding what a fall time is.

data

  • freq:5.6Hz V1:11.6V V2:2.08V deltaT:40ms (measure function 58.56ms) time between 90% and 10% of the first falling edge of the waveform
  • freq:11.2Hz V1:13.4V V2:3.6V deltaT:30ms (measure function 39.3ms)
  • freq:56.75Hz V1:10.1V V2:7.1V deltaT:7.5ms (measure function about 3ms)
  • freq:6cycles per77.2s 77.7mHz V1:9.76V V2:1.76V deltaT 40ms(measure function about 51.8ms) note:waiting for the trigger sucks

Analysis

I neglected to record the amplitude when I was collecting data making it impossible to calculate the fall time as far as I could tell from information gleaned from http://en.wikipedia.org/wiki/Rise_time.

I feel the most accurate rise time is 51.8ms measured on the slowest frequency. I feel the smaller values for the fall time measured with the oscilloscope are inaccurate because at the higher frequency's the voltage has a sharp drop before reaching 10% of the peak voltage.



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