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: Equivalent Capacitance

  1. Mar 8, 2007 #1
    1. The problem statement, all variables and given/known data

    In the diagram V = 12.0V, C1 = 23 uF, C2 = 4.00 uF, C3 = 12.0 uF and C4 = 9.00uF. Calculate the equivalent capacitance of the system.

    http://img403.imageshack.us/img403/6346/eqam8.jpg [Broken]

    2. Relevant equations

    Just combinding capacitors in parallel and in series.

    3. The attempt at a solution

    This question is giving me a headache when it should be simple. I must be overlooking something stupid, and hopefully someone will please lead me in the right direction.

    I start by taking capacitors C1 and C3, which are in series, and combine them :
    1/C13 = 1/24 + 1/12
    1/C13 = 3/24
    C13 = 8

    Doesn't that leave C13, C2, and C4 in parallel? (this is where i'm getting sidetracked i think. the middle one is throwing me for a bit of a loop). In parallel, that would just be 8+4+9 = 21 uF, which is not the answer. The answer should be 5.14 uF.

    I'd appreciate any pointers.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Mar 8, 2007 #2

    berkeman

    User Avatar

    Staff: Mentor

    No, only C13 and C2 are in parallel for the next step.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook