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Homework Help: Phasor circuit problem: 1 resistor, 1 capacitor, 1 inductor, 1 Voltage source

  1. Apr 3, 2007 #1
    1. The problem statement, all variables and given/known data

    What value of [itex]\omega[/itex] will cause the forced response [itex]v_0[/itex] in the circuit below to be zero?

    http://img248.imageshack.us/img248/1854/problem934ao5.jpg [Broken]

    2. Relevant equations

    Phasor eqs.

    3. The attempt at a solution


    If I substitute [itex]V_1\,=\,0[/itex], then I get:


    How do I use this to find [itex]\omega[/itex]?
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Apr 3, 2007 #2


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    If you want Vo to be zero, the impedance of the series connection of the capacitor with the inductor must be zero.
    You got the impedance of the capacitor wrong.
    [tex]Z_C = \frac{-j}{\omega C}[/tex]
    [tex]Z_L = j \omega L[/tex]
  4. Apr 3, 2007 #3
    http://img99.imageshack.us/img99/4333/problem934part2xc6.jpg [Broken]



    We want [itex]V_{OUT}[/itex] to be zero:





    Is that right?
    Last edited by a moderator: May 2, 2017
  5. Apr 3, 2007 #4


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    Yes, the impedance is zero at the resonant frequency [tex]\omega_0 = \frac{1}{(LC)^\frac{1}{2}} = \frac{1}{10}[/tex]
    Last edited by a moderator: May 2, 2017
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