Hi MIKE.

03-Apr-04 09:31:40, MIKE ROSS wrote to Jasen Betts

 MR> Some fish have the ability to detect electric fields.

Fields or currents? :)

 MR> Speaking of electric fields, would a conductor moving through a
 MR> stationary electric field produce an emf?

 That's how condensor microphones work.

 You've got two grids with a voltage between between them
 and in the space there's a conductive diaphragm, sound waves move the
 diaphragm and change in position of the diaphragm changes its potential
 it's a very high impedance output, I think electret microphones used a
 minituarised version of this with an internal amplifier to reduce the
 impedance and boost the signal.

 Electrostatic loudspeakers use the same effect in reverse.

 MR> I know it happens the other way around for example an antenna,
 MR> where a changing electric field sets up an emf along the radial.
 MR> However, in the case of the antenna there is also a supporting
 MR> magnetic component.

isn't the magnetic component caused by the electrons moving up and down the
antenna wire..

 MR> We all know in the case of a stationary magnetic field the moving
 MR> conductor will have an emf induced. Will it also happen if we
 MR> substitute an electric field? If it does what is this effect
 MR> called?

I don't know what it's called.

 -=> Bye <=-

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