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Homework Help: What is the capacitance of each capacitor?

  1. Mar 22, 2008 #1
    Two capacitors when connected in parallel give an equivalent capacitance of 9.00 pF and an equivalent capacitance of 1.55 pF when connected in series. What is the capacitance of each capacitor?

    in parallel:
    C1 + C2 = 9.00 pF

    in series:
    (1/C1) + (1/C2) = (1/1.55pF)

    My attempt:
    (C1 + C2)/(C1*C2) = 1/1.55

    (C1*C2)/(C1+C2) = 1.55

    (C1*C2)/9 = 1.55

    C2 = (9*1.55)/C1

    From here i don't know what to do...
    Last edited: Mar 22, 2008
  2. jcsd
  3. Mar 22, 2008 #2
    You have two equations and two unknowns. Solve for one in terms of another and plug it into a 2nd equation.
  4. Mar 22, 2008 #3
    Just put C1 = 9 - C2 from the first equation, into the second equation and solve the resulting quadratic equation.
  5. Mar 22, 2008 #4
    thanx guys :)
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