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Homework Help: Please help -Capacitors in series and parallel

  1. Jun 28, 2011 #1


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    Please help :( -Capacitors in series and parallel

    1. The problem statement, all variables and given/known data
    Find the relationship between C and C1 to make C equivalent= C

    The diagram is as shown below:-
    Code (Text):

                                            |                |
                                             =C1            = C
                                            |                |
    2. Relevant equations
    C parallel= C1 + C2 + C3......
    1/C series= 1/C1 + 1/C2 + 1/C3

    3. The attempt at a solution

    So on the right most of the diagram, C1 and C are in series, hence their combined capacitor is C1(C)/C1+C. And since the combined capacitor is in parallel with the other C1, C equivalent is C1(C)/C1+C + C1 = C

    However, I can't seem to solve that particular equation by making C as the subject....

    Please help..

    The answer provided by the textbook is:
    C=C1 (1+ square root of 5) / 2

    Last edited by a moderator: Jun 29, 2011
  2. jcsd
  3. Jun 28, 2011 #2


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    Re: Please help :( -Capacitors in series and parallel

    I guess my diagram is messed up even though i tried to fixed it, but yeah,

    C1 is in series with C

    and those two combined are in parallel with C1.....
  4. Jun 29, 2011 #3


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    Staff: Mentor

    Re: Please help :( -Capacitors in series and parallel

    Let's see some of the mathematical steps you've taken to try to solve for C.
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