Author Topic: Avalanche And Zener breakdown in Diode  (Read 2671 times)

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Offline elixierTopic starter

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Avalanche And Zener breakdown in Diode
« on: August 24, 2007, 12:32:34 PM »
Being a small question it troubles me a lot.
Plz help me understand the Avalanche as well As the Zener breakdown in detail.
Means when the Zener breakdown occurs and when the Avalanche breakdown occurs and wih suitable V/I charateristics plz?
What is the difference betwwen the two breakdown mechanism in the Diode?
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Offline paulstreats

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Re: Avalanche And Zener breakdown in Diode
« Reply #1 on: August 24, 2007, 06:44:55 PM »
The main difference is that zeners are designed to reverse conduct at a much lower voltage

here is a site that will explain the differences and mechanisms in a lot of detail::

[url]http://people.seas.harvard.edu/~jones/es154/lectures/lecture_2/breakdown/breakdown.html[/ur]

and a quick excerp

Quote

"Avalanche breakdown is caused by impact ionization of electron-hole pairs.?While very little current flows under reverse bias conditions, some current does flow.?The electric field in the depletion region of a diode can be very high. Electron/holes that enter the depletion region undergo a tremendous acceleration.? As these accelerated carriers collide with the atoms they can knock electrons from their bonds, creating additional electron/hole pairs and thus additional current.?As these secondary carriers are swept into the depletion region, they too are accelerated and the process repeats itself.?This is akin to an avalanche where a small disturbance causes a whole mountainside of snow to come crashing down.? The efficiency of the avalanche effect is characterized by a so-called multiplication factor M that depends on the reverse voltage (Equation 1).


 

Equation 1: Multiplication Factor



 


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