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Op-amp integrator and differentiator in real-life

  1. Mar 5, 2009 #1
    I've gone through some light theory on op-amps and can understand that fully. What I don't understand are the real-life applications for integrator and differentiator. What does the output signal looks like? Can somebody shed some light on these?
  2. jcsd
  3. Mar 5, 2009 #2
  4. Mar 5, 2009 #3
    If you use an inverter configuration op amp with a resistor R in series with the neg input and a feedback capacitor C from the output to the neg input, it is an integrator. Put a square wave in and get a triangle wave out. If you put occasional pulses V volts high and T sec wide in, the output will be proportional to the input voltage V divided by R times pulse width T divided by capacitance C.

    If you replace the input R with a capacitor, and use a feedback resistor instead of a capacitor, you will get positive and negative spikes out (differentiated signal), good for triggering scalers, etc.
  5. Mar 5, 2009 #4
    if you integrate a constant, you get a ramp. and that you could use to deflect an electron in a CRT to draw a horizontal line, and to gradually move that line a little lower vertically each sweep.

    maybe about as interesting as vacuum tubes with today's technology, tho.
  6. Mar 6, 2009 #5
    Thanks for the replies guys! I can't wait to be able to put theory into practise. All these sound like gold, espescially the PID controllere sounds something I'm going to need quite a lot.
  7. Mar 10, 2009 #6
    You can also use them to calculate velocity, & position from accelerometer.
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