# The graph given below represents the I-V characteristics of a zener diode. Which part of the curve is relevant for operation as voltage regulator?

$(a)\;a-b \\ (b)\;b-c \\ (c)\;c-d \\ (d)\;d-e$

Zener diode is used in reverse bias and need a constant voltage for voltage regulation.
So $a-b$ is the relevant part
Hence a is the correct answer.