Zener diode as a Voltage Regulator notes

zener diode

1. Zener Diode Voltage Regulator

2. Zener Diode

3. V-I Characteristics

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) 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) 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. 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

8. Load Regulation: Input unregulated d.c. voltage = Fixed V Line regulation: RL = Fixed k Ω

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