I need some kind of AGC. A Zener clipper won't work because I need to preserve the sine wave. I'm thinking an Op-Amp with a JFET voltage to resistance circuit in the feedback loop. Since both cycles of the input are being rectified positive, the op amp's -V supply can be GND (no need for + & - power supply for op amp, only +). So in summary, I have a full wave rectified unfiltered sine wave that varies between 1v and 100v peek and I want to convert this to a constant 5v peek. Any help would be appreciated.