Zener Diode

A Zener diode is a special type of diode designed to allow current to flow not only in the forward direction (like a normal diode) but also in the reverse direction when the voltage reaches a specific value called the Zener breakdown voltage.

Working Principle (GIF Reference)

• In the GIF, the Zener diode is placed in reverse bias.
• When the applied voltage is below the breakdown voltage (e.g., 5.6V), almost no current flows through the diode.
• Once the reverse voltage reaches the Zener voltage (Vz), the diode starts conducting in reverse, maintaining a stable output voltage across the load.
• This makes the Zener diode very useful for voltage regulation in circuits.

Key Features

• Zener Breakdown Voltage (Vz): Fixed value (e.g., 5.1V, 5.6V, 10V, etc.), at which the diode conducts in reverse.
• Reverse Bias Operation: Unlike normal diodes, Zener diodes are specifically designed to work in reverse bias mode.
• Voltage Regulation: Keeps the output voltage nearly constant even if the input voltage changes.

Applications

• Voltage Regulator – Provides a stable reference voltage.
• Overvoltage Protection – Protects sensitive circuits from high voltage surges.
• Waveform Clipping & Shaping – Used in signal conditioning.

👉 In the first GIF, the Zener diode clamps the voltage at 10V, showing its regulation property.

👉 In the second GIF, as the supply voltage increases, the Zener begins to conduct at 5.6V, keeping the voltage across it stable.