A classic analog application is the full-wave precision rectifier (absolute value) function. Many variations exist on this theme, each with its own supposed (often rather minor and sometimes downright ...

A classic analog application is the precision active full-wave rectifier. Many different implementations exist of this theme, each with its own supposed advantages. However, one circuit element needed ...

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 ...