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Homework Help: Finding Rth of an RLC circuit

  1. Dec 20, 2009 #1
    I want to know how to find the R thevenin of an RLC circuit. Do I short the inductor and open the capacitor? or do I remove both capacitor and inductors?
  2. jcsd
  3. Dec 20, 2009 #2

    The Electrician

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    Gold Member

    There's more than one kind of RLC circuit. You should show a schematic.
  4. Dec 25, 2009 #3
    It depends on whether you have a DC circuit or an AC circuit.

    1) DC

    A) Since the reactance of an inductor is given by:
    XL = j*(2 * pi * f * L)
    and (f = 0) in a DC circuit, so inductor is replaced by a short circuit. ( An element with zero reactance or resistance)

    B) For the capacitor:
    Xc = 1 / (j*(2 * pi * f * C))
    Substituting zero for f, the answer will be infinity (an open circuit).

    2) AC

    The value of frequency is substituted in each case and a reactance will be obtained for each element. Neither the inductor nor the capacitor will be replaced with short or open.
    Last edited: Dec 25, 2009
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