Electret is a solid
dielectric with a
permanent electric
field. Electret is an
abbreviation for ELECTRic magnET(
electret is the electrical
equivalent to a magnet)
In
production of electret the
material is
melted and
subjected to an
electric field. The
material is then
cooled while
still in the
electric field. It will
retain the
charge it got(similar to a
magnet that
will
retain the
magnetic field it was
subjected to) nearly
infinitely.
Electret is mostly used in
cheaper electrostatic headphones and
electret
condenser microphones.