A Zener diode is one in which the reverse breakdown occurs due to electron quantum tunneling under high electric field strength called Zener effect. Now during the negative half cycle, the zener diode is in forward biased connection.
As the negative voltage increases till forward threshold voltage, the diode starts conducting and the negative side of the output voltage is limited to the threshold voltage.
As voltage increases, the kinetic energy velocity of the electrons also increases and the covalent bonds are more easily disrupted, causing an increase in electron hole pairs.
The current through a forward-biased PN junction is proportional to e raised to the power of the forward voltage drop. While designing a voltage regulator using zener diode, the latter is chosen with respect to its maximum power rating.
Zener Diode as a voltage clamper In a circuit involving AC input source, different from the normal PN diode clamping circuita Zener diode can also be used. Breakdown voltage is typically much, much greater than forward voltage.
For convenience it is used normally. The Zener walkout phenomenon therefore does not occur here, and the buried Zeners have voltage constant over their entire lifetime. Zener breakdown occurs at low reverse voltage whereas avalanche breakdown occurs at high reverse voltage.
Why not just size the resistor for a very high value of resistance, thus severely limiting current and keeping power dissipation figures very low?
As we have gone through the first part of the article we know what is Zener diode and what is the basic principle of operation. However, as we will see, it cannot accomplish this task.
This results in varying negative electric field intensity, generating an electric potential across the junction.