You mean like a diode?
http://jas.eng.buffalo.edu/education/pn/cv/index.html

-----Original Message-----
From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org]
On Behalf Of Andrew O'Grady
Sent: Friday, May 18, 2007 11:32 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] Off-the-shelf product with known C-V

Hello Everyone,

I am using the Keithley 590CV for capacitance-voltage measurements on my
MEMS sensor which actuates when a voltage is applied. I have been getting
some odd results, and the Keithley 590CV has not been calibrated in a long
time and may not be working properly. Does anyone know of a product that I
could purchase and test with a known C-V curve? Perhaps an accelerometer? I
would prefer that i could use it on a probe station, and the capacitance
change should be at least 10fF.

Thanks,
Andrew O'Grady