Semiconductor
Semiconductor is a substance, such as germanium or silicon, that has an electrical conductivity that increases with temperature and is intermediate between that of a metal and an insulator. The behavior may be exhibited by the pure substance ( intrinsic semiconductor) or as a result of impurities ( extrinsic semiconductor).
Air, glass, most plastics, and rubber are insulators, and then there are some materials called semiconductors, that seem to be good conductors sometimes but much less so at other times.
Semiconductors such as germanium and silicon are neither conductors nor insulators of electricity, but possess unique electrical properties that make them excellent signal detectors.
A semiconductor is a substance that can act as an electrical conductor or insulator depending on chemical alterations or external conditions.
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