Hello. I'm looking for an electrometer schematic. I've got already several sets, but before realizing my PCB, I wish to see more and more versions.

 

Google returns 300,000 hits, including this one - http://www.eskimo.com/~billb/emotor/chargdet.html.

 

Thanks for yr reply. I know this site, but I'm looking for something more sophisticated using IC's and able to work with very low current in order of a few fA.