In voltage regulation using a zener diode, the diode is operated in which mode?

In voltage regulation using a zener diode, the diode is operated in which mode?

• A. Forward biased
• B. Reverse biased
• C. Shorted
• D. Unbiased

Answer: (B)

Voltage regulation with a zener diode relies on operating the diode in reverse-biased breakdown. When reverse biased and the input voltage exceeds the zener breakdown voltage, the diode starts to conduct, but the voltage across it stays nearly constant at the zener voltage. This stable voltage is what we use to regulate the output, with current through the zener varying as needed to supply the load. If the diode were forward biased, it would behave like a normal diode and drop only about 0.7 V, offering no stable reference for higher voltages. An unbiased or open-circuit diode would not provide regulation at all.

Voltage regulation with a zener diode relies on operating the diode in reverse-biased breakdown. When reverse biased and the input voltage exceeds the zener breakdown voltage, the diode starts to conduct, but the voltage across it stays nearly constant at the zener voltage. This stable voltage is what we use to regulate the output, with current through the zener varying as needed to supply the load.

If the diode were forward biased, it would behave like a normal diode and drop only about 0.7 V, offering no stable reference for higher voltages. An unbiased or open-circuit diode would not provide regulation at all.