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In electronics, the Zener effect (employed most notably in the appropriately named Zener diode) is a type of electrical breakdown, discovered by Clarence Melvin Zener. It occurs in a reverse biased p-n diode when the electric field enables tunneling of electrons from the valence to the conduction band of a semiconductor , leading to numerous ...
Zener and avalanche diodes, regardless of breakdown voltage, are usually marketed under the umbrella term of "Zener diode". Under 5.6 V, where the Zener effect dominates, the IV curve near breakdown is much more rounded, which calls for more care in choosing its biasing conditions.
Clarence Melvin Zener (December 1, 1905 – July 2, 1993) was the American physicist who in 1934 [1] was the first to describe the property concerning the breakdown of electrical insulators. These findings were later exploited by Bell Labs in the development of the Zener diode , which was duly named after him. [ 2 ]
Zener can refer to: . Zener diode, a type of electronic diode; Zener effect, a type of electrical breakdown which is employed in a Zener diode; Zener pinning, the influence of a dispersion of fine particles on the movement of low- and high angle grain boundaries through a polycrystalline material
The Zener effect is primarily exhibited by reverse-biased diodes and bipolar transistor base-emitter junctions that breakdown below about 7 volts. The breakdown is due to internal field emission, since the junctions are thin, and the electric field is high. Zener-type breakdown is shot noise.
This effect called Zener breakdown, occurs at a precisely defined voltage, allowing the diode to be used as a precision voltage reference. The term Zener diodes is colloquially applied to several types of breakdown diodes, but strictly speaking, Zener diodes have a breakdown voltage of below 5 volts, whilst avalanche diodes are used for ...
The effect can be minimized. Motchenbacher & Fitchen (1973, pp. 291–292) describe a noise source using a Zener diode (also suitable for an avalanche diode). Some commercial microwave noise generators use avalanche diodes to create a large excess noise figure that can be turned off and on.
There is a hysteresis effect; once avalanche breakdown has occurred, the material will continue to conduct even if the voltage across it drops below the breakdown voltage. This is different from a Zener diode, which will stop conducting once the reverse voltage drops below the breakdown voltage.