Search results
Results From The WOW.Com Content Network
A subsurface Zener diode, also called a buried Zener, is a device similar to the surface Zener, but the doping and design is such that the avalanche region is located deeper in the structure, typically several micrometers below the oxide. Hot carriers then lose energy by collisions with the semiconductor lattice before reaching the oxide layer ...
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 ...
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.
Breakdown voltage is a parameter of a diode that defines the largest reverse voltage that can be applied without causing an exponential increase in the leakage current in the diode. Exceeding the breakdown voltage of a diode, per se, is not destructive; although, exceeding its current capacity will be. In fact, Zener diodes are essentially just ...
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 symbol as shown here is acceptable but could be confused with a Schottky Barrier Diode, which is a different kind of diode, and not a Zener diode. The bends on the cathode bar are different. See the Schottky diode page . To be technically correct we should also show the ISO standard symbol which has only one bend, at 90-degrees.
This effect is used to advantage in Zener diode regulator circuits. Zener diodes have a low breakdown voltage. A standard value for breakdown voltage is for instance 5.6 V. This means that the voltage at the cathode cannot be more than about 5.6 V higher than the voltage at the anode (though there is a slight rise with current), because the ...
Zener diodes These can be made to conduct in reverse bias (backward), and are correctly termed reverse breakdown diodes. 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 ...