Question

In breakdown region, a Zener diode behaves as a

• A. constant current source
• B. constant voltage source
• C. constant resistance source
• D. constant power source

Answer 1

Answer: (B)

When the reverse voltage across a zener diode exceeds the breakdown voltage $V_Z,$ the current increases very sharply. In this region, the curve is almost vertical. It means voltage across zener diode is constant at $V_Z,$ even though the current through it changes. Therefore, a zener diode behaves as a constant voltage source.