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Homework Help: Inductive and Capacitive Reactances - AC circuits

  1. Aug 31, 2009 #1
    If we increase the driving frequency in a circuit with a purely capacitive load, do (A) amplitude Vc and (B) amplitude Ic increase, decrease or remain the same?
    If instead the circuit has a purely inductive load, do (C) amplitude V L and (D) amplitude I L increase, decrease or remain the same?
    Relevant Equations:
    Xc= 1/wC = V/I
    X L= wL = V/I
    Attempt at solution:
    I don't understand how to apply there equations here to get the answer...So please tell me how to find the answer here... And also can you tell me whether there is a link between this question and this https://www.physicsforums.com/showthread.php?t=333786&goto=newpost (which i recently posted) ?
  2. jcsd
  3. Aug 31, 2009 #2


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    Homework Helper

    let's re-simplify some things:

    Inductance (you can assume this is as resistance for the time) of a capacitor XC=1/(2πfC)

    For an inductor XL=2πfL

    Can you find expressions for the Voltage and current through the capacitor and inductor?
  4. Aug 31, 2009 #3
    Vc= Ic x Xc
    V L=I L x X L
  5. Aug 31, 2009 #4


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    Staff: Mentor

    Small typo -- you meant "reactance" instead of "inductance"... (if you want to fix it, I'll just delete this post of mine to clean up)
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