In my previous article on common op-amp circuits, I mentioned that operational amplifiers were used for analog computing, where analog circuits simulated the behavior of complex systems. That article ...

A fixed-frequency signal generator that can produce outputs simultaneously at multiple phases such as 45°, 90°, 135°, and 180° is sometimes needed for testing multi-channel analog-to-digital ...

In a balanced op-amp circuit, the op-amp inputs see equal impedances looking into the circuit. Balanced circuits provide better performance by cancelling some input errors and have a simple R F /R I ...

And here it is, modelled using LTSpice. It is the same circuit as the classic simple precision rectifier (set to pass the negative half-sine), but with the non-inverting input of the op-amp connected ...