Introduction
• • AZener diode is a special type of p-n
junction diode designed to operate in reverse
bias.
• • Discovered by Clarence Zener.
• • Mainly used for voltage regulation in
electronic circuits.
3.
Symbol & Construction
•• Symbol: Similar to a diode but with bent
edges.
• • Heavily doped p-n junction.
• • Thin depletion region allows breakdown at
low voltage.
• • Specially designed for reverse bias
operation.
4.
Working Principle
• •Forward bias: Behaves like a normal diode.
• • Reverse bias: Conducts after reaching Zener
breakdown voltage (Vz).
• • Breakdown voltage remains nearly constant,
independent of current.
• • Equation: V = Vz (constant voltage across
Zener diode).
5.
VI Characteristics
• •Forward region: Acts like a normal diode.
• • Reverse region: Very small leakage current
before breakdown.
• • Zener breakdown: Sharp increase in current
after Vz.
• • Voltage across diode remains constant.
6.
Six Characteristics ofReverse
Biasing
• 1. Reverse Leakage Current – tiny current
before breakdown.
• 2. Zener Breakdown Voltage (Vz) – fixed
breakdown point.
• 3. Sharp Breakdown – sudden rise in current
after Vz.
• 4. Voltage Regulation – maintains constant
voltage.
• 5. Temperature Dependence – Vz varies
slightly with temperature.
7.
Applications
• • Voltageregulator in power supplies.
• • Surge protector in circuits.
• • Provides reference voltage.
• • Used in wave shaping circuits.
• • Switching and clamping circuits.
8.
Advantages & Limitations
•Advantages:
• ✔ Simple, cheap, and reliable.
• ✔ Provides stable reference voltage.
• Limitations:
• ✘ Limited to low power devices.
• ✘ Affected by temperature changes.
9.
Conclusion
• • Zenerdiode is a special diode designed to
work in reverse bias.
• • It maintains a constant voltage after
reaching breakdown voltage.
• • Widely used in voltage regulation and
protection circuits.
