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Homework Help: Capacitors in a circuit / Calculate total capacitance

  1. Apr 8, 2012 #1
    1. The problem statement, all variables and given/known data

    Capacitors are connected as shown in this diagram:


    C1 = 2 μF, C2 = 1 μF. What is the total capacitance of the system in between the terminals A and B?

    2. Relevant equations

    For capacitors C1 and C2 connected in series, [itex]\dfrac{1}{C_\Sigma}=\dfrac{1}{C_1}+\dfrac{1}{C_2}[/itex]

    For capacitors C1 and C2 connected in parallel, [itex]C_\Sigma=C_1+C_2[/itex]

    3. The attempt at a solution

    The problem here is that my answer doesn't match that in the book. So I just wanted to check if you guys get the same answer as me.

    The three rightmost capacitors C1 have a total capacitance of 2/3 μF.
    They are connected in parallel to a C2-capacitor, their overall capacitance is 1+2/3=5/3 (μF).
    Then we have a C1 in series with what we calculated above in series with yet another C1, which yields 1/(1+3/5)=5/8 (μF).
    Last, we have a C2 in parallel with what we calculated above, which yields 1+5/8=13/8=1.625 (μF).

    The book gives 1.58 μF.
  2. jcsd
  3. Apr 8, 2012 #2


    User Avatar

    Staff: Mentor

    Looks like your answer is correct and the book's is not.
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