The Comparator
Comparator
The Basics
The comparator, unlike the previous amplifiers I’ve covered, requires no components other than the op-amp itself. The inverting and non-inverting inputs are used to compare two voltages. The higher of the two inputs will drive the output to the corresponding supply rail. For example, if the voltage applied to the non-inverting input is higher than the voltage at the inverting input, the output will be whatever voltage is applied to the positive supply rail of the op-amp. I think the figures below are the easiest way to understand the comparator operation. Also, because of the simple nature of this amplifier topology, I pared this post down to the basics.
Schematic:
Simulations:
Gain Derivation (sort of)
There isn’t really a gain derivation. Just remember, the output will go to the supply rail of the highest input: the negative rail for the inverting input and the positive rail for the non-inverting input.