By your first post, I understood that your problem is the heating, right? Did you analyze the capacitive power supply idea? If you use a simple divider with power resistors, the heating will be great, even for very small currents, but with the capacitive power supply you may get some tens of mA without noticeable heating. You could drop the voltage with a capacitor and a Zener to say, 9V, and then use a 78L05 to regulate to 5V for the small PIC with A/D. It is perfectly possible to use an opto-coupler spending 5mA, plus perhaps 1mA for the PIC. Using SMD and creative board layout it should be possible to accommodate all this in 1/2 square inch. Best regards, Isaac Em 13/9/2011 07:34, Forrest Christian escreveu: > I'm not picky. Peak would be fine, as would be RMS, since I can=20 > basically do math to adjust either. I don't need a fancy true-rms=20 > reading or anything like that. > > -forrest > > On 9/12/2011 5:17 PM, M.L. wrote: >> On Sun, Sep 11, 2011 at 8:21 AM, M.L. wrote: >>> On Sat, Sep 10, 2011 at 11:17 PM, Forrest Christian= wrote: >>>> I keep hoping to come across a really teency isolation transformer or >>>> similar, and/or a simple, clean circuit that does what I need it to... >>>> But alas, after hours and hours of looking, I'm no closer. >>>> >>>> I'm hoping someone can give me a hint as to what I might want to be >>>> looking for. >>>> >>>> -forrest >>> Do you just need the peak voltage? The RMS? Or are you sampling at >>> some frequency? >>> >>> -- >>> Martin K. >>> >> Do you need the peak voltage or the RMS or what? >> --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .