How do capacitors restore their charge?

Question

I understand the basics of how capacitors work, but I can’t seem to wrap my head around this.

If there is a non-conducting material in between the two plates, and you place a capacitor into a DC circuit:

1. How do electrons pass through?
2. How does a capacitor restore itself back to neutral?

Maybe I have a misunderstanding of how they work, but I would appreciate if someone can explain this to me!

Answer 1

1. They don't, that's what makes it a capacitor.
2. When you remove the battery/voltage source, the capacitors will essentially run current in reverse to discharge.

Answer 2

You may be missing a few key-concepts:

• electric fields attract and repell charges (depending on their poalrity)
• if charges can move freely, like in a metal, an el.filed will create a (temporary) current (influence), until there is a balance between sepating field and counter field by the separated charges
• if charges can't move, like in molecules, a neutrally charged object can still separate + and - charges; BECAUSE there is no conductivity, the molecule will be polarized by the field (+q to one end, -q to the other); as a result the molecular dipols will turn (macro-parameter: $\epsilon_r$)
• when influenced (=separated) charges can flow away (e.g. through an external electrical resistance), there is no way for the capacitor to recharge by its own (gone is gone)
• when they can't, applying a field will separate charges (the polarized plates will act as a dipol agaon), and when the field disappears, charges will recombine again
• isolate everything and the netto charge will not change (remaining zero if uncahrged in teh beginning, or pos or neg, if precharged beforehand)
• missing isolation means charges diappearing (try electrostatic experiements on a day with high humidity)