Capacitors - surely they break the circuit?
Hi, wondering why a capacitor means charge is stored at either end if there’s an air gap or insulating material between the two plates. Surely that would just break the circuit and it was switch off? Why does that not happen?
Okay, consider this kind of situation. I won't call it a thought experiment or anything, but it's just a visualisation.
You have the two plates, initially without any sort of potential difference across them. Suddenly you introduce a potential difference, and all of a sudden there is a current in the circuit, after all this electric field displaces some electrons or charge carriers of some sort throughout the circuit. If we're talking electrons, they're sucked (scientific term. It really is. heh, not really) into the anode of the source and shot out form the cathode. Eventually, however, there is no net flow.
Why is there no net flow? Well, clearly on the positive side, the buildup of positive charges on one side of the capacitor vs. the buildup of negative charges on the other side of our capacitor, pulled through by our potential difference, the opposing "push" of the capacitors potential difference, by nature of the buildup of charges across it, is cancelling out that of the source.
I was using the case of a capacitor in series with some random source, like a D battery or something.
Anyway, that's just how a capacitor builds up charge in simple terms. The PD generates an electric field, this separates charge, charge builds up on capacitor, electric field builds up across the spacing in the capacitor, it opposes the electric field of the source, there is eventually no net flow of charge.
Anyway, now that I look at your question, I don't think I've answered it.
The circuit isn't broken. The purpose of a capacitor is to charge up and store charge. Then once the source is disabled, that charge is released, albeit in the opposite sense. That's just for the above example, they have many more uses (i.e. in LRC and whatnot circuits, it gets pretty interesting.)
You have the two plates, initially without any sort of potential difference across them. Suddenly you introduce a potential difference, and all of a sudden there is a current in the circuit, after all this electric field displaces some electrons or charge carriers of some sort throughout the circuit. If we're talking electrons, they're sucked (scientific term. It really is. heh, not really) into the anode of the source and shot out form the cathode. Eventually, however, there is no net flow.
Why is there no net flow? Well, clearly on the positive side, the buildup of positive charges on one side of the capacitor vs. the buildup of negative charges on the other side of our capacitor, pulled through by our potential difference, the opposing "push" of the capacitors potential difference, by nature of the buildup of charges across it, is cancelling out that of the source.
I was using the case of a capacitor in series with some random source, like a D battery or something.
Anyway, that's just how a capacitor builds up charge in simple terms. The PD generates an electric field, this separates charge, charge builds up on capacitor, electric field builds up across the spacing in the capacitor, it opposes the electric field of the source, there is eventually no net flow of charge.
Anyway, now that I look at your question, I don't think I've answered it.
The circuit isn't broken. The purpose of a capacitor is to charge up and store charge. Then once the source is disabled, that charge is released, albeit in the opposite sense. That's just for the above example, they have many more uses (i.e. in LRC and whatnot circuits, it gets pretty interesting.)
Hey, thank you so much for this extensive response! I found it very helpful. Thanks again
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