- #1
Alex Hughes
- 54
- 13
I understand the basics of how capacitors work. If you hook one up to a power source, negative charge will build up on one plate, and positive charge will build up on the other plate. As the charges build up, an electric field forms between the plates and a potential difference is established. This potential difference stops once it reaches that of the battery. This is because eventually, the charge builds up to a point where there is no electric field between one of the terminals of the battery and one of the plates.
However, what I'm confused on is how the charges build up on the plates to begin with. If you look at a capacitor, it consists of two plates separated by a certain distance. To me this is an open circuit? My book says that originally an electric field exists between the two terminals of the battery which drives the electrons to one plate, and pulls them away from the other. But this would mean that electrons still flow even if the circuit isn't complete.
If that was the case why couldn't you just take one wire and attach it to the negative terminal, take another wire and attach it to the positive terminal, and bring them near each other (without touching) and have a current? Do electrons still flow up to the point of a break in a circuit? If so, that makes zero sense to me. It would mean you would have current even when a circuit isn't complete. Would love some help. Thanks.
However, what I'm confused on is how the charges build up on the plates to begin with. If you look at a capacitor, it consists of two plates separated by a certain distance. To me this is an open circuit? My book says that originally an electric field exists between the two terminals of the battery which drives the electrons to one plate, and pulls them away from the other. But this would mean that electrons still flow even if the circuit isn't complete.
If that was the case why couldn't you just take one wire and attach it to the negative terminal, take another wire and attach it to the positive terminal, and bring them near each other (without touching) and have a current? Do electrons still flow up to the point of a break in a circuit? If so, that makes zero sense to me. It would mean you would have current even when a circuit isn't complete. Would love some help. Thanks.
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