dlloyd:
I am not sure that will work because the capacitor needs to discharge since the sinusoid amplitude may change and it needs to follow the negative peaks.
Just an assumption I made because the peak detector sample circuit provided in your link didn't have one. No problem, all that's needed is an additional resistor in parallel with the capacitor. Use values that provide whatever RC time constant you need.
Hi Dloyd, thanks for the reply. Other things can't do with your suggestion is use a regular diode. I'll use a zener/schotty.