Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Unit Question with Capacitance

  1. Jan 31, 2004 #1

    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!
  2. jcsd
  3. Jan 31, 2004 #2
    That has to be a typo.

    1 Farad is defined as 1 Coul./Volt

    You have 4.7 nF x 30 V = 141 nC
  4. Jan 31, 2004 #3
    Okay, that makes a lot more sense.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook