What is Zener Diode ? Zener Diode as a Voltage Regulator Explained (with solved Examples)

In this video, the basics of Zener Diode is explained and how the Zener Diode can be used as a voltage regulator in the various circuit is explained (with solved examples).

By watching this video, you will learn the following topics:

0:25 What is Zener Diode

5:40 Zener Diode as a Voltage Regulator

9:08 Example 1

12:17 Zener Diode as a Voltage Regulator with variable load

15:25 Example 2

17:25 Zener Diode as a Voltage Regulator with variable source voltage

20:32 Example 3

23:00 Zener Diode as a Voltage Regulator with variable series resistor

25:39 Example 4

What is Zener Diode:

Unlike the normal diode, the Zener diode is intended to use in the reverse bias condition. (Although it can work in both direction)
When the applied reverse bias voltage is more than the breakdown voltage (Known as the Zener voltage), the diode starts conducting in the reverse direction.

And after this Zener voltage, even if the applied voltage is increased, the voltage across the Zener diode almost remains constant. And that's why it is used as a voltage regulator in many applications.

The Zener diodes with a wide range of Zener voltages (2V to 200V, or even higher) are available commercially.
And by changing the doping concentration, it is possible to change the Zener voltage of the Zener diode.

Conditions to operate the Zener diode in the breakdown region (or as a voltage regulator)

1) The reverse bias voltage should be more than the Zener voltage
2) The Zener current should be between knee current (Izk) and the maximum allowable Zener current (Izm)

Zener diode approximations:

1) Zero Zener Resistance (Zener Resistance is negligible)
Under the breakdown region, the Zener diode can be represented as a voltage source in series with the Zener resistance. And typically this resistance used to be a few Ohms)
But for the analysis, the Zener resistance can be neglected.

2) Zener Knee Current is Zero ( Knee Current is negligible)
To operate the Zener diode in the breakdown region, or as a voltage regulator, the current through the Zener diode should be more than the Knee Current.
But for analysis, it can be assumed that this current is negligible.

Zener Diode as a Voltage Regulator:

In this video, the Zener diode voltage regulator circuit is explained (with examples) considering the different cases.

1) The load resistor is Variable (Source and the current limiting series resistor are fixed)
2) The Source/Supply Voltage is Variable (The load resistor and the current limiting series resistor are fixed)
3) The current limiting series resistor is Variable (Source and the load resistors are fixed)

And the example is solved for each case.

This video will be helpful to all the students of science and engineering in understanding, what is Zener diode and how it can be used as a voltage regulator.

#ZenerDiode
#ZenerDiodeAsVoltageRegulator


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