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

Homework Help: Capacitors in series questions

  1. Sep 17, 2006 #1
    Good day everyone. Please help with these questions.

    The circuit is a series of 3 capacitors with a battery.
    C1 = C
    C2 = 2C
    C3 = 3C

    How do you find the voltage across the first capacitor in a series of 3?

    How do you find the charge Q on the first capacitor?

    How do you find the equivalent capacitance Ceq for this combination of capacitors in series?

    I had these questions on a test and know the answers but not how to arrive at them. I am usually quick on the uptake but teaching this basic stuff adequately is apparently beneath my professor and the text is terrible! (stay away from Young & Geller!)

    Thanks for any help you can provide.
  2. jcsd
  3. Sep 17, 2006 #2


    User Avatar

    The equivalent capacitance of a series of n capacitors is done by the expression:
    [tex]\frac{1}{C_{eq}}=\sum_{k=1}^n \frac{1}{C_k}[/tex]
    The charge in all capacitors is the same.
    Charge, voltage and capacitance are related by:
    [tex]q = CV[/tex]
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook