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Capacitor and inductors

  1. Nov 13, 2015 #1
    Physically, can someone explain why does not the voltage on the capcitor change immediatly?
    and why does not the current in the inductor also do?
  2. jcsd
  3. Nov 13, 2015 #2


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    The voltage on the capacitor is a function of the amount of electric charge on its two plates. It takes time, and work, for the charge to accumulate.
  4. Nov 13, 2015 #3


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    As for the capacitor:

    I = C * dV/dt

    So if dt is infinite small, dV/dt and thus I will become infinite high.

    As for the inductor:

    V = L * dI/dt

    So if dt is infinite small, dI/dt and thus V will become infinite high.
    Practically, if you feed an inductor by a DC-current and switch it off, the inductor will immediately produce a (long) spark, thereby keeping up the current.
  5. Nov 13, 2015 #4


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