Finding a Good DC Peak Detection Circuit

[propergomper]

hi i was wondering if anyone could tell me of any good dc peak detection circuits. the voltages i am measuring are varying by one hundredth of a volt.
i have been using the peak detector on the wqikipedia website but the circuit doesn't seem to store the peak voltage as the reading on the dmm drops once i change the conditions of the circuit

any help is greatly appreciated

thanks

 

[berkeman]

The one at wikipedia.org is the correct basic one to use:

http://en.wikipedia.org/wiki/Peak_detector

Remember that unless you reset it, it should hold the peak value until the load resistance (your DVM?) bleeds off some of the charge on the storage capacitor. If you want longer hold times, you need to increase the capacitance (within reason), or raise the load impedance (maybe use a FET input opamp buffer stage?), or do some kind of sampling of the output voltage and store those values digitally somewhere.