Encyclopedia > Zener diode

  Article Content

Zener diode

A conventional solid-state diode will not let current flow if reverse-biased (up to a breakdown voltage). By exceeding the breakdown voltage a conventional diode is destroyed in the breakdown due to excess current and overheating. In case of forward-bias (in the direction of the arrow) the diode exhibits a voltage drop of roughly 0.7 volt. The voltage drop depends on the type of the diode.

A Zener diode exhibits almost the same properties, except the device is especially designed so as to have a greatly reduced breakdown voltage, the so-called Zener voltage. 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. A reverse-biased Zener diode will exhibit a controlled breakdown and let the current flow to keep the voltage across the Zener diode at the Zener voltage. For example, a 6.2 volt Zener diode will exhibit a voltage drop of 6.2 volt if reverse biased. However, the current is not unlimited, so the Zener diode is typically used to generate a reference voltage for an amplifier stage.

The breakdown voltage can be controlled quite accurately in the doping process. Tolerances up to 0.05% are available though the most widely used tolerances are 5% and 10%.

The effect was discovered by the American physicist Clarence Melvin Zener[?].

Another type of diode designed to break down under reverse bias, by a different mechanism to the Zener diode, is the avalanche diode.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Battle Creek, Michigan

... 31.6% of all households are made up of individuals and 12.1% have someone living alone who is 65 years of age or older. The average household size is 2.43 and the ...

 
 
 
This page was created in 22.3 ms