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Homework Help: Capacitors in series

  1. Mar 29, 2006 #1
    if there are two capacitors in series and the capacitance of one is known how would i find a value for the other?
  2. jcsd
  3. Mar 29, 2006 #2


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    I am assuming that you know the total capacitance (the capacitance of the two combined), right? Otherwise it's impossible to answer:eek:

    For two capacitors in series, the total capacitance is given by
    [itex] {1 \over C_{tot}} = {1 \over C_1} + {1 \over C_2} [/itex], ore, if you prefer [itex] C_{total} = { C_1 C_2 \over C_1 + C_2} [/itex].

    You know the total capacitance and C_1 (say). Then you can easily solve for C_2.

  4. Mar 30, 2006 #3
    [tex] {1 \over C_{tot}} = {1 \over C_1} + {1 \over C_2} [/tex]

    Well, what is the exact problem? Like he said above, you would need to know the total capacitance, OR the charge and the potential :-) seeing how C=Q/V. When dealing with electricity, capacitors, and resistors... It's best to write down what you are given, have a list of equations next to you and look at the equations to see which ones match up with what you need :-)
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