Zener Breakdown And Avalanche Breakdown

Avalanche breakdown (or 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.

Which breakdown occurs first Zener or Avalanche?

The avalanche breakdown occurs in the thick region, whereas the Zener breakdown occurs in the thin region. After the avalanche breakdown, the junction of the diode will not regain its original position, whereas after the Zener breakdown the junction regains its original position.

What is Zener breakdown in semiconductor?

When reverse bias is increased, the electric field at the junction also increases. At some stage the electric field breaks the covalent bond, thus the large number of charge carriers are generated . This is called Zener breakdown.

What is Zener breakdown voltage?

Breakdown voltage for commonly available Zener diodes can vary widely from 1.2 V to 200 V. For diodes that are lightly doped the breakdown is dominated by the avalanche effect rather than the Zener effect. Consequently, the breakdown voltage is higher (over 5.6 V) for these devices.

What are the 4 types of avalanches?

4 Types of Avalanches

• Loose Snow Avalanche. They are common on steep slopes and are seen after a fresh snowfall.
• Slab Avalanche. Loose Snow Avalanches in turn could cause a Slab Avalanche, which are characterized by a the fall of a large block of ice down the slopes. ...
• Powder Snow Avalanche. ...
• Wet Snow Avalanche.

Why Zener breakdown is reversible?

The collisions happening in avalanche breakdown dissippiate thermal energy and may cause damage of normal diodes. Whereas zener doesn't have much thermal dissippiation. Thus after reaching zener breakdown voltage zener remains undamaged, can be used again.

What is the main cause of Zener breakdown?

The main cause of zener breakdown is high doping concentrations. The breakdown is a condition when upon increasing the voltage in small amounts; we experience a massive current flow in the device. Zener breakdown occurs when we apply reverse bias to a heavily doped diode.

Is Zener breakdown occurs in reverse bias?

No worries!

What is zener formula?

The maximum current is calculated by dividing the power rating by the Zener voltage: I=P/V = 3W/12V = 0.25A.

What are different types of breakdown in diode?

The breakdown of a diode happens when you apply a reverse bias across the diode. There are two types of breakdown, one is Zener breakdown and the other is Avalanche breakdown. Zener breakdown happens due to field ionization(Tunneling effect) and Avalanche breakdown happens due to impact ionization.

Why is PN junction used?

P-N junction diode can be used as a photodiode as the diode is sensitive to the light when the configuration of the diode is reverse-biased. It can be used as a solar cell. When the diode is forward-biased, it can be used in LED lighting applications.

Is Zener voltage negative?

Zener Diode I-V Characteristics From the I-V characteristics curve above, we can see that the zener diode has a region in its reverse bias characteristics of almost a constant negative voltage regardless of the value of the current flowing through the diode.

What is the maximum Zener power?

Power rating: The maximum power the Zener diode can dissipate; given by the product of voltage across the diode and the current flowing through. Typical values are 400 mW, 500 mW, 1 W, and 5 W; for surface mounted, 200 mW, 350 mW, 500 mW, and 1 W are typical. Voltage tolerance: typically ±5%. 2.

What is leakage current in diode?

Solution : (i) The leakage current of diode is the current that the diode will leak when a reverse voltage is applied to it. <br> (ii) In a reverse biased diode, some current flows through the depletion region. <br> This current is called leakage current . It is dependent on minority carriers.

What are the 7 causes of an avalanche?

Avalanches are caused by four factors: a steep slope, snow cover, a weak layer in the snow cover and a trigger. Roads and railway tracks may be rerouted to reduce risks. Safe avalanches may be triggered in dangerous snow packs. Avalanches can travel up to 90 km/h.

What are the 2 main types of avalanches?

There are two main types of snow avalanches—sluffs and slabs. Sluff avalanches occur when the weak layer of a snowpack is on the top. A sluff is a small slide of dry, powdery snow that moves as a formless mass. Sluffs are much less dangerous than slab avalanches.

What are the 3 parts of an avalanche path?

Although underlying terrain variations, such as gullies or small boulders, can create The three parts of an avalanche path: starting zone, track, and runout zone.

Is Zener unidirectional or bidirectional?

Unidirectional TVS Devices The simplest unidirectional TVS device is a Zener or avalanche diode as shown in Figure 1. For negative voltage from cathode to anode the TVS has high conductivity above a forward diode drop.

How many types of Zener breakdown are there?

A zener diode has two distinctly different breakdown mechanisms: zener breakdown and avalanche breakdown. The zener breakdown voltage decreases as the temperature increases, creating a negative temperature coefficient (TC).

Why is Zener connected in parallel?

No, Zener diodes must not be connected in parallel for the purpose of increasing the allowable power dissipation. If two Zener diodes are connected in parallel, the one with the lower Zener voltage will conduct most of the Zener current, possibly exceeding its allowable power dissipation.