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A Zener diode is a special type of diode designed to reliably allow current to flow "backwards" (inverted polarity) when a certain set reverse voltage, known as the Zener voltage, is reached. Zener diodes are manufactured with a great variety of Zener voltages and some are even variable.
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 ...
In the Zener diode, the concept of PIV is not applicable. A Zener diode contains a heavily doped p–n junction allowing electrons to tunnel from the valence band of the p-type material to the conduction band of the n-type material, such that the reverse voltage is "clamped" to a known value (called the Zener voltage), and avalanche does not ...
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.
The transfer characteristic has exactly the same shape of the previous basic configuration, and the threshold values are the same as well. On the other hand, in the previous case, the output voltage was depending on the power supply, while now it is defined by the Zener diodes (which could also be replaced with a single double-anode Zener diode).
These diodes can indefinitely sustain a moderate level of current during breakdown. The voltage at which the breakdown occurs is called the breakdown voltage . 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.
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; Clarence Zener, the American physicist after whom the diode, effect, and pinning are named; Karl Zener, the ...
Here, the load current I R2 is supplied by the transistor whose base is now connected to the Zener diode. Thus the transistor's base current (I B) forms the load current for the Zener diode and is much smaller than the current through R 2. This regulator is classified as "series" because the regulating element, viz., the transistor, appears in ...