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I am was reading some answers on whether capacitors store charge (which they don't, as far as I know), on this website, and then one response got me thinking:

There are some ways to store or accumulate static electric charge. A Van de Graaff generator is a device that accumulates electric charge. This can actually store a net charge. This device stores excess charge with respect to ground and touching it makes your hair stand up.

Still, this device with respect to itself should be neutral and so stores no net charge, so my question is, does Van de Graaff generator really store charge, or is it like a capacitor?

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The dome of a Van de Graaff generator can be thought of as an "isolated" conducting sphere of capacitance $C=4 \pi \epsilon_0 R$ where $R$ is the radius of the sphere and the other plate is the earth.
The charge is stored on the outside of the sphere.

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  • $\begingroup$ so, this means a Van de Graff doesn't store charge also, sorry for the inconvenience $\endgroup$ – phenolicdeath Sep 7 '17 at 9:30
  • $\begingroup$ The VdG stores charge on its dome. $\endgroup$ – Farcher Sep 7 '17 at 10:48
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Capacitors store equal and opposite charges on their plates. Even so, engineers and most physicists do talk (knowing what they mean) about capacitors storing charge. A few pedants like me qualify this by saying that the net charge stored is zero. The sphere of a V de G is, effectively, one 'plate' of a capacitor. Its surroundings form the other 'plate'.

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  • $\begingroup$ still, this does not explain the point I am talking about, can a V de G gen and a capacitor be like the same thing? $\endgroup$ – phenolicdeath Sep 4 '17 at 10:07
  • $\begingroup$ Doesn't my last sentence answer your question? $\endgroup$ – Philip Wood Sep 4 '17 at 15:01

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