Physics307L F09:People/Koch/Figuring out Oscilloscope

Links

• http://en.wikipedia.org/wiki/Oscilloscope
• http://en.wikipedia.org/wiki/Fall_time
• http://en.wikipedia.org/wiki/Rise_time
• Fourier series applet
• Oscilloscope from ZTEC (Link from Lorenzo Trujillo)

First, measuring basics of a wave

1. Hook up scope to measure a wave w/ BNC cables (do we want to use terminators?)
2. Measure characteristics of a sine wave
   • Measure peak to peak voltage (thus amplitude) and measure the period (thus frequency)
     1. First, use the grid on the oscilloscope screen ("divisions" are the dotted lines)
     2. Next, use the cursors
     3. Finally, use the "measure" functions.

AC Coupling

• Square wave, not pinning. 2.5 Hz, amplitude 8.6 +/- 0.1 V
  • Fall time using cursors:
    1. 61 ms; w/ measure (60 +/- 0.5) ms
    2. 62 ms
    3. 61 ms
• What RC constant does this imply, and what is the TDS 1002 supposed to be?
• AC coupling mystery: Max DC offset, 2.5 Hz, max amplitude (so it's pinning at 13V): Ask students to explain what is going on.

FFT

1. Find the frequency of a sine wave using FFT "Math" function
2. Look at the harmonics in triangle and square wave
3. Compare with what you see on this applet: Fourier series applet

Other features

• Display:Persist
• Acquire:Average (average out noise)
• Display:XY