Editing Diode (section)

=== Other functions ===
A semiconductor diode's current–voltage characteristic can be tailored by selecting the [[semiconductor materials]] and the [[doping (semiconductor)|doping]] impurities introduced into the materials during manufacture.<ref name="Turner" /> These techniques are used to create special-purpose diodes that perform many different functions.<ref name="Turner" /> For example, to electronically tune radio and TV receivers ([[varactor diode]]s), to generate [[radio frequency|radio-frequency]] [[oscillation]]s ([[tunnel diode]]s, [[Gunn diode]]s, [[IMPATT diode]]s), and to produce light ([[light-emitting diode]]s). Tunnel, Gunn and IMPATT diodes exhibit [[negative resistance]], which is useful in [[microwave]] and switching circuits.

Diodes, both vacuum and semiconductor, can be used as [[Noise generator#Shot noise generator|shot-noise generators]].