4. Zener Diode as Voltage Regulator
• One of the most important applications of Zener Diode is Voltage Regulation.
• Zener Diode is used in electrical as well as an electronic circuit for voltage
regulation.
• To use a Zener Diode as Voltage Regulator we must be connected the Zener Diode
in reverse bias.
• So there are some questions arise that How Zener Diode regulate voltage and why
Zener diode regulate voltage in reverse bias, not in forward bias.
5. What is Voltage Regulation?
• The method or process of keeping constant voltage in a circuit even if the
power supply or load changes is called Voltage Regulation.
• There are some electrical and electronic devices are available which cannot
withstand voltage fluctuation. So for this purpose Voltage Regulation is
needed.
6. Why Regulate Voltage in Reverse Bias, not in Forward Bias?
• In forward bias the Zener diode act as a normal PN Junction diode. The Zener Diode
has a very low threshold voltage(0.7V for Silicon and 0.3V for Germanium).
• That means when we connect a Zener Diode in forward bias, it will conduct current
when the applied voltage goes above that threshold voltage.
• The minimum reverse voltage after which the Zener diode conducts current in
reverse bias is called Zener voltage.
• So when we connect a Zener diode in reverse bias it will only conduct current when
the applied voltage goes above the Zener Voltage. Zener voltage ratings which are
available in the market are 6V, 12V, 24V, etc.
7. How does a Zener Diode Regulate Voltage?
Change in Input Voltage (Line Regulation)
(1) When the input voltage goes above the break down the Zener
diode will start conducting current so a voltage drop will be
produced in the series resistor and the output voltage across the
load remain constant. The conduction of current through the
Zener diode will be increased if the input voltage is increased.
Thus the Zener diode keeps the constant voltage across the load.
Change in Load (Load Regulation)
(2) When we increase the load, that means the load will draw more
current, then the flow of current through the Zener Diode will
decrease and it maintains a constant voltage across the load.
(3) When we decrease the load, that means the load will draw less
current, then the flow of current through the Zener Diode will
increase and the constant voltage across the load will maintain.
https://www.etechnog.com/2019/04/zener-diode-voltage-regulator.html
