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Strange current

  1. Jan 18, 2015 #1
    How is the current that pushes electricity through the space between the two plates of the capacitor called?
  2. jcsd
  3. Jan 18, 2015 #2

    Stephen Tashi

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    Are you thinking of "displacement current"?
  4. Jan 18, 2015 #3
    Yes, thank you.
  5. Jan 18, 2015 #4
    How is this current connected to the turbulent current and the surface current?
  6. Jan 18, 2015 #5


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    No current is flowing "through" the capacitor. Current flowing onto one plate creates a charge which sets up an electric field which again repels some charge on the other plate. Therefore you can "load" the capacitor with a charge by connecting it to a voltage source. You can then transport this charge by disconnecting the capacitor and moving it somewhere else.
  7. Jan 19, 2015 #6
    But why and how does AC pass through the capacitor?
  8. Jan 19, 2015 #7


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    It doesn't, because AC is cycling, the polarity of the charge on each of the plates of the capacitor is also constantly alternating
    at the frequency of the AC signal (voltage)

  9. Jan 19, 2015 #8


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    It does not. An alternating current will charge and discharge one plate, which means that the electrical field will change which again will change the charge on the other plate. A change in the charge means that a current will pass out of or come onto the plate. Thus, it seems as if current "passes through", but in reality it is interaction between current, charge and field.

    To repeat the basics: Q = C*V. If things change over time, you get dQ/dt = C*dV/dt, and dQ/dt is the current out of or onto the plate.
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