# Cancel displacement current?

Discussion in 'Electronic Design' started by Robert kenworth, Nov 30, 2006.

1. ### Robert kenworthGuest

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.

2. ### Guest

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

3. ### jasenGuest

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