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Homework Help: Capacitor and Inductor in Parallel

  1. Feb 12, 2009 #1
    1. The problem statement, all variables and given/known data

    How do I combine these into an equivalent impedence? I'm dealing with complex impedence, but I'm not sure how to make them into an equivalent impedence.

    2. Relevant equations

    3. The attempt at a solution

    I guess Zeq= 1/[(1/Zc)+(1/ZL)].
    Is this right?
  2. jcsd
  3. Feb 12, 2009 #2
    Or do I replace the capacitor by an open circuit and inductor by a short?
  4. Feb 12, 2009 #3
    It looks pretty good to me, however I'd like to clarify a little terminology.

    Z represents a complex value called impedance with both real and imaginary parts. Often however it is given as a single number which represents just the magnitude without the angle. As magnitude it is always positive.

    Zc & ZL aren't correct because those values are always imaginary with no real part. Instead, the term X is used and it's called reactance.

    Capacitive reactance (Xc) is always negative and Inductive reactance (XL) is always positive.

    With no real parts the formula would be Xeq = 1/[(1/Xc) + (1/XL)].
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