Some time ago I've assembled a simple circuit of full-wave precision rectifier to feed signal from 50Hz AC current transformer to Atmega ADC input.
Here this unit schematic:
Here this unit schematic:
(picture taken from from sound.westhost.com)
Everything was fine, except strong self-oscillation of first opamp on one of half-waves (after some time TL072 become hot!). Bypass D1 with a tiny 0805 SMD capacitor 560pF completely removed this "bug" =)
And at last I've changed opamp to LM358. No significant changes and distortions on output. D1,D2: 1N4148.
Opamp is powered +/- 15V.