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AngelofMusic
Jan31-04, 01:00 PM
Hello,

We haven't covered capacitance in class yet, but our lab involves the use of capacitors, so I thought I'd throw out a general question.

We were asked to use the MOS FET Electrometer to measure charge, and we were given the formula:

Q = CV

Where C is the capacitance, and V is the potential difference. C is measured in Farads and V in volts.

I'm just confused because in the sample calculations provided by the lab handout, we had:

Qinit = CV = 4.7x10^-9 [F] X 30 [V] = 141 [nF]

How come the unit for charge ended up being in nanofarads, and not in coulombs or nanocoulombs or anything like that?

Any clarifications would be appreciated!

gnome
Jan31-04, 01:31 PM
That has to be a typo.

1 Farad is defined as 1 Coul./Volt

You have 4.7 nF x 30 V = 141 nC

AngelofMusic
Jan31-04, 01:36 PM
Okay, that makes a lot more sense.

Thanks!