1. Zener Diode Voltage Regulator

2. Zener Diode Voltage Regulator
A zener diode is also called a voltage-reference, voltage regulator or breakdown diode.
The zener diode is a silicon PN junction device, which differs from a semiconductor diode, in the sense, that it is operated in the reverse breakdown region.
Also, the breakdown voltage of a zener diode is set by carefully controlling the doping level during manufacturing process.

3. Zener Diode Voltage Regulator
Doping level of normal diode is 1: , where as in the zener diode the doping level is 1: 105.
Both P and N regions of zener diode are little more doped then normal diode.
Zener diode is always reverse connected i.e. it is always reverse biased.
The main application of zener diode is it can be used as a voltage regulator to provide a constant voltage from a source whose voltage may vary over sufficient range.
When forward biased, its characteristics are just those of ordinary diode.

4. Zener Diode Voltage Regulator
When we studied about the diode characteristics, it was found that under reverse bias, there is a small amount of current due to the drifting of the minority charge carriers. But as the reverse potential is increased beyond a level, suddenly the current increase, which is called as 'breakdown' and the corresponding voltage is called as breakdown voltage.
The zener diode is a device which operates on the reverse bias breakdown voltage.

5. Zener Diode Voltage Regulator
Zener Diode Voltage Regulator Circuit
The most common use of zener diode is to use it as a voltage regulator.
Pictured is a very simple voltage regulator circuit requiring just one zener diode and one resistor. As long as the input voltage is a few volts more than the desired output voltage, the voltage across the zener diode will be stable.

6. Zener Diode Voltage Regulator
Zener Diode Voltage Regulator Calculator
Below is a link to a simple to use zener diode voltage regulator calculator. For any given output voltage and current requirement it will calculate the value of power rating of the current limiting resistor and zener diode.

7. Zener Diode Voltage Regulator
References