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Questions About Inductors

  1. Dec 3, 2012 #1
    Hello everybody,
    First of all I want to thank you all for this great forum.

    My question is if a superconductor inductor is charged with a certain voltage and then it is
    open circuited what will happen.
    My very basic understanding tells me that if the inductor is not a superconductor (it has
    intrinsic resistance) the induced EMF will first accumulate opposite charges at each end
    of the inductor and then the charges will move from the higher potential end to the lower
    potential end in a decaying manner (a simple RL circuit) and all the energy will be dissipated
    as heat due to the inductor intrinsic resistance, am I right?

    And for a superconductor inductor, the same will take place however, the charges will remain
    at each end (acting like a capacitor) storing the energy in the form of electric field as long as the temperature is low enough to maintain the superconductivity condition otherwise, the
    law of conservation of energy will be broken because energy have nowhere to go, again am I

    Thank you again for all your efforts.

  2. jcsd
  3. Dec 3, 2012 #2


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    Gold Member

    First, you don't "charge" an inductor with a voltage, you do it with a current.

    When inductors are "open-circuited" they spark across the gap as the circuit opens, with the energy of the spark equivalent to the energy in the inductor. Why would a superconducting inductor act any differently in principle?
  4. Dec 3, 2012 #3
    Thank for replying.
    What I have understood from your reply is that when the inductor
    is open-circuited it will have to spark (giving that no clamping method
    is provided), and therefore all of my assumption (which is based on
    the assumption that you could open-circuit an inductor without having
    it to spark) don't even have a reason to occur.
  5. Dec 3, 2012 #4


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    Gold Member

    Yes, that is correct, otherwise it would be possible to have a the same amount of current flowing through an open circuit as through the closed circuit, which just doesn't make any sense. How could you have current in an open circuit?
  6. Dec 3, 2012 #5
    Thank you very much, that clarified a lot for me.
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