There a few.

PI Physik Instrumente, you can check their web page
MTI Advanced Product Division also makes capacitance sensing  system and
sell components like pre-amps.  They have a fairly knowledgable  tech. rep.
Paul Slazas, 518-785-2389


Quanmin Su

At 10:35 PM 03/23/1999 -0500, you wrote:
>Hi!
>Are there commerical suppliers of capacitance sense ckts (transresistance
>amps) which can sense 10's of fF's (or tenths or nA's)
>
>Thanks
>Madan
>
>
>
>