Electric Current in a Capacitor: What is it Called?

In summary, the current that passes through a capacitor is not a traditional current, but rather a result of the changing charge and electric field within the capacitor. This is known as the displacement current and is connected to the behavior of AC signals.
  • #1
Chemist@
115
1
How is the current that pushes electricity through the space between the two plates of the capacitor called?
 
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  • #2
Are you thinking of "displacement current"?
 
  • #3
Yes, thank you.
 
  • #4
How is this current connected to the turbulent current and the surface current?
 
  • #5
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.
 
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  • #6
But why and how does AC pass through the capacitor?
 
  • #7
Chemist@ said:
But why and how does AC pass through the capacitor?

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)

Dave
 
  • #8
Chemist@ said:
But why and how does AC pass through the capacitor?
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.
 

1. What is an electric current in a capacitor?

An electric current in a capacitor is the flow of electric charge between the two plates of the capacitor. This current is caused by the buildup of charge on the capacitor's plates, which creates an electric field between them.

2. How is an electric current in a capacitor different from an electric current in a wire?

An electric current in a wire is the flow of electrons through a conducting material, while an electric current in a capacitor is the movement of electric charge across an insulating material (the dielectric) between the plates of the capacitor.

3. What is the unit of measurement for an electric current in a capacitor?

The unit of measurement for an electric current in a capacitor is the ampere (A). It is the same unit used to measure electric current in a wire.

4. What is the role of a capacitor in an electric circuit?

A capacitor plays a crucial role in an electric circuit by storing and releasing electric charge. It can act as a temporary energy source, smoothing out fluctuations in the current and voltage of the circuit.

5. Can an electric current in a capacitor be constant?

No, an electric current in a capacitor cannot be constant. This is because as more charge accumulates on the plates of the capacitor, the electric field between them increases, making it more difficult for further charge to flow. As a result, the current gradually decreases until the capacitor reaches its maximum charge.

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