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Homework Help: Capacitors in Series and Parallel homework

  1. Feb 28, 2010 #1
    1. The problem statement, all variables and given/known data

    In Fig. 25-22, each capacitance C1 is 7.2 µF, and each capacitance C2 is 4.8 µF

    25-22.gif

    (a) Compute the equivalent capacitance of the network between points a and b.

    (b) Compute the charge on each of the three capacitors nearest a and b when Vab = 450 V.

    (c) With 450 V across a and b, compute Vcd.


    2. Relevant equations

    Q=CV

    3. The attempt at a solution

    I tried figuring the total capacitance, but I can't tell what is series and what is parallel! In series I know that the potential differences add up in series and they are the same in parallel, and the opposite is true for charge. Please help!
     

    Attached Files:

  2. jcsd
  3. Feb 28, 2010 #2

    Delphi51

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    Homework Helper

    The three capacitors on the right hand end are in series.
    Capacitances in series "add" according to the formula
    1/C = 1/C1 + 1/C2 + 1/C3
    Then you can replace the original circuit with a simpler equivilent one with the three capacitors replaced by the one.

    Do it again - this time the two capacitors on the end are in parallel.
     
  4. Feb 28, 2010 #3
    Okay, thank you so much!
     
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