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AC Resonance

  1. Aug 23, 2012 #1
    Having carried outan AC Resonance experiment recently, I find that I have missed a simple step in the procedure- or left it out of my lab book - grrr!

    For a parallel RLC circuit I was asked to observe voltage across the inductor (coil) at a constant current setting.
    I'm assuming the trace to be a peak at resonant frequency. Could someone confirm this & elaborate if possible, please.

    I didn't record this & although just a small part of the report I should include it.
     
    Last edited: Aug 23, 2012
  2. jcsd
  3. Aug 23, 2012 #2

    berkeman

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    Staff: Mentor

    The term "constant current" implies a DC condition, not an AC resonant condition. Could you please clarify?
     
  4. Aug 23, 2012 #3
    I think I know that the poster means that the AC current does not change. Constant current does not have to mean it is DC.
    They have said that there is a peak at the resonant frequency this sounds like a 100% AC question.
     
  5. Aug 23, 2012 #4
    Constant current setting probably refers to the combination of the position of the output dial on the power supply and the operating mode of the power supply.

    I expect the circuit consists of a load that is a parallel RLC circuit driven by a current source of constant amplitude and variable frequency. The voltage across the load will thus be a maximum when the impedance of the load is a xxxxxx . This xxxxxx occurs when .....................
     
  6. Aug 24, 2012 #5
    Yes, the current is A.C & is set to an output which does not change & the frequency is swept over a range.

    RLC circuit.jpeg
     
  7. Aug 24, 2012 #6
    We have done more or less the same thing but for a series circuit. In that case the voltage was kept constant (it was shown on a multimeter) and we observed the AC voltage across the series resistor using an oscilloscope. Resonance could be obtained quite easil by changing the frequency.
     
  8. Aug 24, 2012 #7
    Roodles, do you have some data from your experiment? Do you have values for the components and settings on the signal generator?

    [ a scan of your lab-book would work too ]
     
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