Zener diode is a silicon semiconductor with a p-n junction that is specifically designed to work in the reverse biased condition. When forward biased, it behaves like a normal signal diode, but when the reverse voltage is applied to it, the voltage remains constant for a wide range of currents. Due to this feature, it is used as a voltage regulator in d.c. circuit. The primary objective of the Zener diode as a voltage regulator is to maintain a constant voltage. Let us say if Zener voltage of 5 V is used then, the voltage becWhat is a Voltage Regulator?
A voltage regulator is a device that regulates the voltage level. It essentially steps down the input voltage to the desired level and keeps it in that same level during the supply. This ensures that even when a load is applied the voltage doesn’t drop. The voltage regulator is used for two main reasons and they are:
- To vary or regulate the output voltage
- To keep the output voltage constant at the desired value in spite of variations in the supply voltage.
Voltage regulators are used in computers, power generators, alternators to control the output of the plant.
Zener Diode as a Voltage Regulator
There is a series resistor connected to the circuit in order to limit the current into the diode. It is connected to the positive terminal of the d.c. It works in such a way the reverse-biased can also work in breakdown condition. We do not use ordinary junction diode because the low power rating diode can get damaged when we apply reverse bias above its breakdown voltage. When the minimum input voltage and the maximum load current is applied, the Zener diode current should always be minimum.
Since the input voltage and the required output voltage is known, it is easier to choose a Zener diode with a voltage approximately equal to the load voltage, i.e. VZ = VL.omes constant at 5 V, and it does not change.
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