Electret Types
There are two types of electrets:
- Real-charge electrets which contain excess charge of one or both polarities, either
- on the dielectric's surfaces (a surface charge)
- within the dielectric's volume (a space charge)
- Oriented-dipole electrets contain oriented (aligned) dipoles. Ferroelectric materials are one variant of these.
Cellular space charge electrets with internal bipolar charges at the voids provide a new class of electret materials, that mimic ferroelectrics, hence they are known as ferroelectrets. Ferroelectrets display strong piezoelectricity, comparable to ceramic piezoelectric materials.
Some dielectric materials are capable of acting both ways.
Read more about this topic: Electret
Famous quotes containing the word types:
“If there is nothing new on the earth, still the traveler always has a resource in the skies. They are constantly turning a new page to view. The wind sets the types on this blue ground, and the inquiring may always read a new truth there.”
—Henry David Thoreau (1817–1862)