ZENER DIODE

ZENER DIODE

·         A Zener diode is a specially doped PN junction device to operate in reverse breakdown region.

Equivalent circuit of zener diode

Biasing of zener diode:

         Forward biasing                                                                                

Reverse biasing:

                                       

• In forward biased condition the normal pn junction diode and zener diode operate in similar fashion.
• In reverse biased condition, the zener diode carries reverse saturation current till the reverse voltage applied is less than the reverse break down voltage(V<V_z). When reverse voltage exceeds reverse breakdown voltage(V>V_z), the current through it changes drastically but voltage across it remains constant.such a breakdown region is called normal operating region of a zener diode.
• The reverse voltage at which the breakdown occurs is called zener breakdown voltage(V_z).

VI characteristics of a Zener diode