0
$\begingroup$

If electrons flow into the first plate which makes it negatively charged, and second plate has electrons leaving it due to the buildup of electrons in the first plate repelling them. Then that second plate will be left will protons that allows electrons to buildup in the first plate due to attraction. This describes charging.

However I'm confused on whether discharging occurs when the first plate has so many electrons that it buildups a force stronger than the external force pushing electrons in there, and starts to flow the other way, and the opposite reaction that I describe above happens.

Or does is discharge when current stops flowing in a circuit or can both methods happen?

If anyone could clear this up, It'd be appreciated. Thanks :)

$\endgroup$
0
$\begingroup$

Well there are a few things that I want to clear up. One plate has a net negative charge and the other a net positive charge. This polarity is a property of an electric field between two capacitor plates. There are no extra protons accumulating. There is no proton motion. The net positive charge is because there is more electrons on one side of the plate than the other. The net positive charge is then the absence of a negative charge on the second plate relative to the first plate.

I think The best way to think of how some current gets through to the second plate is to make an analogy with a selective membrane. diffusion without a membrane occurs because of concentration gradients. Diffusion eventually leads to an even distribution of two different solutes within a solvent. In the capacitor your dielectric acts as a selective membrane. Selective membranes only activate for specific gradients which are the conditions of the system. Similarly some electrons get through the electric field if a capacitor reaches a certain charge. The current that passes through depends on the dielectric and how close the plates are similar to the property of the membrane deciding what it allows to pass through it.

In a DC circuit when charging is complete no current passes through except for some.small leakage. Discharging occurs if the voltage supply is interrupted I.e. a short or an open circuit. Then the capacitor discharges because the voltage of the battery is no longer felt. In an AC circuit there is no well defined boundary between charge and discharge states both happen constantly an simultaneously since AC current fluctuates

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.