Zener diode as a Voltage Regulator
The Zener diode makes its use as a voltage regulator due to the following property :
When a Zener diode is operated in the breakdown region, the voltage across it remains practically constant for a large change in the current.
A simple circuit of a voltage regulator using a Zener diode is shown in the figure. The Zener diode is connected across load such that it is reverse biased.
The series resistance R absorbs the output voltage fluctuations so as to maintain constant voltage across the load.
If the input dc voltage increases, the current through R and Zener diode also increases. So, voltage drop across R increases, without any change in the voltage across zener diode.
I-V Characteristics
