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Parallel resonance by varying frequency

  1. Mar 29, 2012 #1
    I understood how it responds by varying the other parameters (L , C...) but how does it respond to changes in frequency? (Honestly speaking, I barely get a thing they're trying to say in my textbook)
  2. jcsd
  3. Mar 29, 2012 #2
    What do you mean by changing the frequency?
    You change the loads (resonant) frequency by changing L, R, C etc.
    You change the source frequency by changing the frequency of the A.C. input.
    When they match resonance occurs.
  4. Mar 29, 2012 #3


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    Staff: Mentor

    At the resonant frequency, the current in L (and the current in C) can reach high values, therefore the voltages across those elements can become high. (High in comparison to the values well away from the resonant frequency.) Where does this high current come from, because the current drawn from the external circuit actually becomes minimal at resonance.

    The current in the inductor comes from the capacitor, and the current in the capacitor comes from the inductor, and very little current is drawn from the external circuit at resonance. It is this high circulating current between L and C that is responsible for the high peak in voltage levels at parallel resonance.
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