# Homework Help: What does this opamp configuration do?

1. May 31, 2013

### dla

1. The problem statement, all variables and given/known data
Trying to figure out what this opamp does but can't pinpoint it.

2. Relevant equations

3. The attempt at a solution
The one with the capacitor looks like an integrator. I attempted to build this circuit to see what it does. At node B I saw a triangle repeating waveform, node A gives a square oscillating waveform and C is some sort of horizontally flipped RC curve which can been seen with the file I attached. Anyone have any idea the name of this circuit?

#### Attached Files:

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• ###### lab1.JPG
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Last edited: May 31, 2013
2. May 31, 2013

### CWatters

Hint: The word you are looking for begins with an "O" and is used to describe a family of systems including a pendulum.

3. May 31, 2013

### dla

I'm still quite not sure.. The only thing that comes to mind is an oscillator?

4. May 31, 2013

### CWatters

Oscillator will do :-)

I suppose "Triangle Wave Oscillator" or "Hysteretic Oscillator" or "Relaxation Oscillator" might get you another half mark.

The right hand op-amp is indeed an inverting integrator. It integrates the "constant" output of the left hand op-amp.

The left hand op-amp is configured as a comparator (with hysteresis) and it's output is a "constant" VCC or -VCC.

You can actually make one by merging the functions each op-amp performs into one op-amp. See wikipedia for that..

http://en.wikipedia.org/wiki/Relaxa...2.80.93based_electronic_relaxation_oscillator

5. Jun 1, 2013

### dla

Perfect explanation, thank you!