Quick Answer: What Is Difference Between Avalanche And Zener Breakdown?

What is Zener breakdown mechanism?

The Avalanche Breakdown and Zener Breakdown are two different mechanisms by which a PN junction breaks.

The Zener and Avalanche breakdown both occur in diode under reverse bias.

The avalanche breakdown occurs because of the ionisation of electrons and hole pairs whereas the Zener diode occurs because of heavy doping..

What is breakdown and its types?

Avalanche breakdown occurs in a pn junction diode which is moderately doped and has a thick junction (means its depletion layer width is high). Avalanche breakdown usually occurs when we apply a high reverse voltage across the diode (obviously higher than the zener breakdown voltage,say Vz).

What is Zener breakdown region?

The zener breakdown occurs in heavily doped p-n junction diodes because of their narrow depletion region. … At zener breakdown region, a small increase in voltage will rapidly increases the electric current. Zener breakdown occurs at low reverse voltage whereas avalanche breakdown occurs at high reverse voltage.

What is meant by avalanche breakdown?

Avalanche breakdown 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.

What is the main cause of Zener breakdown?

What is Zener Breakdown? The Zener breakdown mainly occurs because of a high electric field. When the high electric-field is applied across the PN junction diode, then the electrons start flowing across the PN-junction. Consequently, expands the little current in the reverse bias.

Why do we use zener diode?

Zener diodes are used for voltage regulation, as reference elements, surge suppressors, and in switching applications and clipper circuits. The load voltage equals breakdown voltage VZ of the diode. The series resistor limits the current through the diode and drops the excess voltage when the diode is conducting.

Why is Zener diode always reverse biased?

When reverse-biased, the rapid switch from “off” to “on” at a particular voltage allows a Zener diode to be used as a voltage reference. In other words, to get the specific behaviour which makes a Zener diode useful, it must be reverse-biased. So that’s why they are always used reverse-biased.

Why does an avalanche breakdown occur?

Avalanche breakdown occurs in a pn junction diode which is moderately doped and has a thick junction (means its depletion layer width is high). Avalanche breakdown usually occurs when we apply a high reverse voltage across the diode (obviously higher than the zener breakdown voltage,say Vz).

How does breakdown occur?

Breakdown occurs when the electric field becomes strong enough to pull electrons from the molecules of the material, ionizing them. The released electrons are accelerated by the field and strike other atoms, creating more free electrons and ions in a chain reaction, flooding the material with charged particles.

What is avalanche and zener breakdown?

The Avalanche Breakdown and Zener Breakdown are two different mechanisms by which a PN junction breaks. The Zener and Avalanche breakdown both occur in diode under reverse bias. The avalanche breakdown occurs because of the ionisation of electrons and hole pairs whereas the Zener diode occurs because of heavy doping.

What is Zener effect and Avalanche effect?

The Zener effect is distinct from avalanche breakdown. … The avalanche breakdown occurs in lightly doped junctions, which produce a wider depletion region. Temperature increase in the junction increases the contribution of the Zener effect to breakdown, and decreases the contribution of the avalanche effect.

What is minimum Zener current?

The minimum Zener knee current, Izk, is used to guarantee a minimum voltage that is less than the Zener voltage. Instead, the current flowing through the Zener must be greater than the maximum reverse current, abbreviated Izr, to absolutely guarantee that the Zener diode will produce the Zener voltage, Vz.

What type of temperature coefficient does the avalanche breakdown has?

Due to increase in temperature, vibrations of atoms increases and thus reduces the mean free path for electrons. Hence, in avalanche breakdown, breakdown voltage increases with increase in temperature. Thus avalanche breakdown is positive temperature coefficient.

What is meant by zener voltage?

Zener Voltage. The voltage that is sufficient for the reverse breakdown condition thus allowing the diode to conduct in the reverse direction.

Is Zener breakdown reversible?

Zener diode breakdown is reversible. i.e. it does not destroy the diode as long as you do not exceed the power rating of the diode.

What causes a Zener diode to fail?

Excessive temperature will destroy a zener diode, and because it both drops voltage and conducts current, it produces its own heat in accordance with Joule’s Law (P=IE). Therefore, one must be careful to design the regulator circuit in such a way that the diode’s power dissipation rating is not exceeded.

What is Zener break down voltage?

A normal p-n junction diode allows electric current only in forward biased condition. … This sudden rise in electric current causes a junction breakdown called zener or avalanche breakdown. The voltage at which zener breakdown occurs is called zener voltage and the sudden increase in current is called zener current.