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Avalanche breakdown (or the avalanche effect) is a phenomenon that can occur in both insulating and semiconducting materials. It is a form of electric current multiplication that can allow very large currents within materials which are otherwise good insulators. It is a type of electron avalanche.
In electronics, an avalanche diode is a diode (made from silicon or other semiconductor) that is designed to experience avalanche breakdown at a specified reverse bias voltage. The junction of an avalanche diode is designed to prevent current concentration and resulting hot spots, so that the diode is undamaged by the breakdown.
Zener breakdown is found to occur at electric field intensity of about 3 × 10 7 V/m. [1] Zener breakdown occurs in heavily doped junctions (p-type semiconductor moderately doped and n-type heavily doped), which produces a narrow depletion region. [2] The avalanche breakdown occurs in lightly doped junctions, which produce a wider depletion region.
When the reverse-bias breakdown voltage is exceeded, a conventional diode will conduct a high current due to avalanche breakdown. Unless this current is limited by external circuits, the diode may be permanently damaged due to overheating at the small (localized) areas of the semiconductor junction where avalanche breakdown conduction is occurring.
The device operates by shunting excess current when the induced voltage exceeds the avalanche breakdown potential. It is a clamping device, suppressing all overvoltages above its breakdown voltage. It automatically resets when the overvoltage goes away, but absorbs much more of the transient energy internally than a similarly rated crowbar device.
An electron avalanche is a process in which a number of free electrons in a ... meaning that avalanches always proceed ... complete avalanche breakdown can ...
As a massive winter storm dumped snow across much of the western U.S., winter sport enthusiasts headed to ski resorts and backcountry slopes ahead of the long Martin Luther King Jr. Day weekend.
At the breakdown field, there is a balance between the production of new electrons (due to impact ionization) and the loss of electrons (due to attachment). Above the breakdown field, the number of electrons starts to grow exponentially, and an electron avalanche ( Townsend avalanche ) forms.