EASA Module 4 · Semiconductors

Zener Voltage Regulator

A Zener diode in reverse holds a steady voltage once the input passes its breakdown voltage. Sweep the input and watch the output stay clamped at the Zener voltage.

Input voltage 10 V

Zener voltage Vz 5.6 V

Input

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Output (regulated)

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Zener Vz

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State

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Below breakdown the diode is off and the output follows the input. Once the input exceeds V_z, the Zener conducts in reverse and clamps the output at V_z — the extra voltage is dropped across the series resistor. This gives a simple, stable reference voltage.