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diode




Symbols for diode
Diode graphic symbols for (a) electron-tube diode; (B) semiconductor diode
An electronic device that allows current to flow in one direction only. Originally an electron tube (valve) having two electrodes (cathode and anode) used as a rectifier, but now extended to include semiconductor devices performing a similar function. The semiconductor diode usually has a single p-n junction. It allows electrons to flow freely in only one direction (n-type material to p-type).

A Zener diode blocks current flow until a critical voltage is reached, when it breaks down and conducts. See also tunnel diode.


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   • ELECTRICITY AND MAGNETISM
   • ELECTRONICS AND SEMICONDUCTORS