Antiferroelectric An antiferroelectic material will be strongly repelled by an electric field. The dipole moments in an antiferroelectric are arranged with an equal number pointing in each direction. An insulator is a compound which does not conduct electricity for all practical purposes. At extremely high voltages, a small amount of conduction will still occur. Conductor A conductor is a material which an electrical current will readily flow through.
Conduction occurs either by the movement of electrons or the movement of ionic atoms or molecules.
Conductors always have a very small amount of resistance to electrical conduction. Semiconductor A material that will conduct a small amperage of electricity when the voltage exceeds some critical value. This minimum necessary voltage corresponds to the energy necessary to excite electrons from a filled energy level called the valence band to an unoccupied energy level called the conduction band. This energy difference is called the band gap. Intrinsic semiconductors are materials which have a small band gap in their pure form.