Electronic Devices - Special-Purpose Diodes - Discussion

Vz = Vi So directly proportional.

Here vz=vl,

By increasing vin I in also increases which will also increase Iz.

When zener reached breakdown region, the voltage across it is constant. So the current through load is fixed. So the current through diode increases.

With increase in Vin causes depletion region in the PN junction to increase towards the either side of terminal and thus due to reverse bias no current will flow via zener diode.

With further increase in the Vin. Zener break down happens due to flow of immobile charge carries and significant current will flow. With further increase in the Vin. Avalanche break down happens and more current will flow.

Answer [a]. When zener reached break down region, the voltage across it is constant. So the current through load is fixed. So the current through diode increases.

When Vin <Vz(Zener Voltage), answer is [c], as zener diode is reversed biased.
When Vin > Vz, answer is [a], as zener diode conducts in reverse biasing after the breakdown voltae(Vz) . And after Vz, current across zener will increase abruptly even for a slight increase in Voltage across it.

If that happens how can a zener be a voltage regulator ?