Cancel displacement current?

Nov 30, 2006 2 Replies

Is it possible to cancel or diminish the displacement current between two charged plates of a flat capacitor by applying an external magnetic field in opposition to the intenal B field of the capacitor?



Robert K.


The expression for the displacement current, \\partial D\\over\\partial t shows that it is proportional to the time derivative of the voltage across the capacitor's plates. That means that to eliminate the dispacement current the voltage must stay constant. Of course, one can apply the external magnetic field to counteract any change in emf across the plates but I do not think that this is what you are after.

The proportionality constant (electric permittivity) is extremely small, so such `currents' are usually on the order of nA. It really is just a mathematical `fudge factor' more than a real current (which is also a very poor name for it) so why would you want to eliminate it? It has nothing to do with leakage across the capacitor.

Alex

not in general, and certainly not in the ideal case,

Bye. Jasen

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