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Homework Help: Capacitance problem

  1. Oct 4, 2009 #1
    1. The problem statement, all variables and given/known data
    Finding the equivalent capacitance of the supplied circuit.

    2. Relevant equations
    For parallel capacitors, C EQ.=C1+C2+C3+..
    For serial capacitors, 1/C EQ.=1/C1+1/C2+...

    3. The attempt at a solution

    The circuit simplification is difficult!

    Attached Files:

  2. jcsd
  3. Oct 4, 2009 #2
    Here, Look at this diagram I drew for you.

    It is actually the same circuit.

    What can you say about the various potential differences?

    Also, take note that the C=Q/V. Over here, C is specified, V and Q are unspecified. How can you make this property useful?

    Attached Files:

  4. Oct 5, 2009 #3
    Thanks! Just tell me one thing, can C3 be ignored because it carries no charge?
  5. Oct 5, 2009 #4
    That would be the case if all the capacitors except C3 have an equal capacitance. The potential difference between b and e in the diagram will be 0 and so no current will flow through C3.

    The circuit will then be simpler.

    And yes, C3 is ignored provided whatever is above is true.
    Last edited: Oct 5, 2009
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