Op Amp

https://en.wikipedia.org/wiki/Operational_amplifier_applications

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• https://mysite.du.edu/~etuttle/electron/circ23.gif

Comparator

Simplest op amp circuit

Non-Inverting amplifier

Amplifies the input voltage. Cannot go below unity.

For high power, output can go through a transistor.

Schmitt Trigger

Uses positive feedback.

Current Sensor

I had to do the math analysis to understand this. Configuration is a differential amplifier.

Real Op Amps

I have a 741 and the lowest it will go is to 1.9V, but it can go all the way up to V+. Which kind of sucks, because it can't easily drive N fets. This may not be an issue, it looks like 2V is essentially off for most N Fets. Need to test.