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Homework Help: Impedance of a Tank Circuit

  1. Sep 12, 2011 #1
    1. The problem statement, all variables and given/known data


    a) Determine the impedance of this circuit.
    b) What is the impedance when [itex] \omega = \frac{1}{\sqrt{LC}} [/itex]

    2. Relevant equations

    3. The attempt at a solution

    EDIT: I got the Z wrong. It's [tex] Z = \frac{L}{C(j{\omega}L - \frac{j}{{\omega}C})} [/tex]

    [STRIKE]For part b, I'm getting that Z = 0 simply by substituting in [itex]\omega[/itex].
    Is this correct? [/STRIKE]

    This gives an impedance of [itex]\infty[/itex]

    I feel more confident is this answer. I'm guessing that the current in the capacitor and inductor are out of phase by [itex]\pi[/itex] causing what appears to be an infinite impedance. I'm still curious as to the exact reason though, if anyone could lend help. Thanks!
    Last edited: Sep 12, 2011
  2. jcsd
  3. Sep 12, 2011 #2

    rude man

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    Homework Helper
    Gold Member

    Y = jwC - j/wL = j(wC - 1/wL) = j(w^2LC - 1)/wL

    Z= 1/Y = jwL/(1 - w^2LC)
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