An avalanche diode is a diode (usually made from silicon, but can be made from another semiconductor) that is designed to break down and conduct at a specified reverse bias voltage. Types of diodes In electronics, a diode is a component that restricts the direction of movement of charge carriers. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor. ... International danger high voltage symbol. ...

The Zener diode exhibits an apparently similar effect, but its operation is caused by a different mechanism, called Zener breakdown. Both effects are actually present in any such diode, but one usually dominates the other. Zener diodes are typically restricted to a few tens of volts maximum, but silicon avalanche diodes are available with breakdown voltages of over 4000 V.[1] Zener diode symbol. ...

Uses

Protection

A common application is protecting electronic circuits against damaging high voltages. The avalanche diode is connected to the circuit so that it is reverse-biased. In other words, its cathode is positive with respect to its anode. In this configuration, the diode is non-conducting and does not interfere with the circuit. If the voltage increases beyond the design limit, the diode suffers avalanche breakdown, causing the harmful voltage to be conducted to earth. When used in this fashion they are often referred to as clamper diodes because they "clamp" the voltage to a predetermined maximum level. Avalanche diodes are normally specified for this role by their clamping voltage V_BR and the maximum size of transient they can absorb, specified by either energy (in joules) or I²t. Avalanche breakdown is not destructive, as long as the diode is not allowed to overheat. An electrical network or electrical circuit is an interconnection of analog electrical elements such as resistors, inductors, capacitors, diodes, switches and transistors. ... attention Electronic and other electric devices are rated at a certain voltage, and considerable damage can be caused by voltage that is higher than that for which the devices are rated. ... Diagram of a copper cathode in a Daniells cell. ... Diagram of a zinc anode in a Daniells cell. ... Avalanche Breakdown is a phenomena that can occur in both insulating and semiconducting materials, it is a form of current multiplication which can allow very large currents to flow in situations where that would normally not be possible. ...

RF noise generation

An avalanche diode generates radio frequency noise, it is commonly used as a noise source in radio equipment. For instance it is often used as a source of RF for a antenna analyzer bridge. Avalanche diodes can also be used as white noise generators. Rough plot of Earths atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including radio waves. ... An antenna analyzer (or noise bridge, or RX bridge) is a Wheatstone bridge where the legs are frequency-dependent complex-valued impedances. ... For other uses of the term white noise, see white noise (disambiguation). ...

See also

• Avalanche photodiode
• Avalanche breakdown
• Zener diode
• Transil
• Varistor
• Voltage stabiliser

Avalanche photodiodes (APDs) are photodetectors that can be regarded as the semiconductor analog to photomultipliers. ... Avalanche Breakdown is a phenomena that can occur in both insulating and semiconducting materials, it is a form of current multiplication which can allow very large currents to flow in situations where that would normally not be possible. ... Zener diode symbol. ... Transils (also know as transil) are electronic components similar to zener diodes that are designed especially to protect electronic circuits against overvoltage peaks. ... A varistor is an electronic component with a significant non-ohmic current-voltage characteristic. ... It has been suggested that this article or section be merged with Linear regulator. ...

References

• Microelectronic Circuit Design - Richard C Jaeger - ISBN 0-07-114386-6
• SemiKRON datasheet for SKa 1/13 Avalanche diode
• Catalog listing for diodes