Normal diode in reverse direction

[electronicslearner77]

Generally in the reverse direction region both normal diode and zener diode exhibit similar characteristics though not exactly same, then only why zener is used as voltage regulator.

 

[srizbf]

similar , in shapes?
what is the breakdown voltage of normal diode compared to zener ?

 

[bowman1710]

There a few reasons why. If you look at a zener graph you will see it is steeper then the normal diode (reverse biased)This results at a certain voltage it can pass higher currents. Normal diodes are not meant to survive the avalanche effect where as the zener is. Zeners (which are meant for breakdown) will be designed that in the in the case of an over voltage they will tolerate a continuous current . The normal diode in this situation will not deal with this situation as well. The doping of the two diodes are different the zener is heavily doped compared to the normal diode.

Have a look at this:

https://www.allinterview.com/showan...difference-between-diode-and-zener-diode.html

 

[electronicslearner77]

Ok the reverse voltage for the normal diode is in the range of 100v. One more doubt is when the diode breaks it is generally said lot of current flows, why is this unwanted situation? Because we are always trying to produce current. please help.

 

[rahdirs]

Ok the reverse voltage for the normal diode is in the range of 100v. One more doubt is when the diode breaks it is generally said lot of current flows, why is this unwanted situation? Because we are always trying to produce current. please help.

Diode breakdown may result in an exponential increase in the current in the diode.As a result,temperature increases because charge carriers increases and physical damage occurs.

 

[FvM]

I fear, the explanations are a bit confusing.

There are essentially two points:

- zener diodes are designed to achieve a stable, mostly temperature independent breakdown voltage. Diode current depends on the external circuit, continuous and pulse power ratings have to be observed

- a "regular diode" has no tightly specified breakdown voltage and neither a defined breakdown characteristic. The actual characteristic is usually less steep than of a zener diode. In addition, breakdown may occur only for part of the diode chip, e.g. at the edge, causing local overheating and damage at relative low reverse current.

 

[LvW]

Ok the reverse voltage for the normal diode is in the range of 100v. One more doubt is when the diode breaks it is generally said lot of current flows, why is this unwanted situation? Because we are always trying to produce current. please help.

No - we are not always trying to "produce current". As far as the Z-diode is concerned, we exploit the fact that there is a certain voltage (a kind of threshold) at which suddenly the I=f(V) characteristic is very steep.
That means: A very large current change for a very small voltage change. With other words: The voltage across the Z-diode is nearly constant and nearly independent on the current change.
This property is exploited for stabilization purposes.