Question

The diode that is specially designed to work only in reverse breakdown region is

Answer 1

Zener diode:

1. Normal PN junction diodes which operate in a reverse-biased condition are called Zener diodes.
2. It works the same as a PN junction in a forward bias condition, but the difference is that it can also conduct when it is connected in reverse bias above its breakdown voltage or threshold.
3. In a reverse-biased p-n junction a small amount of reverse saturation current flows which is almost independent of the reverse-bias voltage.
4. However, if the reverse voltage exceeds a certain critical value the current suddenly rises to a very large value.
5. This is referred to as the breakdown in diodes.
6. Unless the diode is specially designed it may damage the diode.
7. Diodes that have adequate power dissipation capabilities to operate in the breakdown region are called breakdown diodes or Zener diodes.
8. The breakdown of a pn junction may occur due to the effects of a strong electric field in the depletion region or the heat generated by the reverse current.
9. The breakdown phenomenon is reversible.
10. The diode returns to normal function on the removal of the applied reverse voltage, provided the reverse current does not exceed the maximum rating prescribed by the manufacturer.
11. Hence, it is operated in a breakdown region.

Therefore, the diode that is specially designed to work only in the reverse breakdown region is the Zener diode.