CET Semiconductor Devices & Circuits 2

Question 1

What is the primary function of a Zener diode in a circuit?

Accepted Answer

Regulate voltage by operating in reverse breakdown

Answer

A Zener diode is specifically designed to maintain a stable reference voltage when reverse biased at its breakdown voltage.

Question 2

In an NPN transistor, which terminal is the source of electrons during normal active-region operation?

Accepted Answer

Emitter

Answer

In an NPN transistor, the emitter injects (emits) electrons into the base region during forward-active operation.

Question 3

A silicon diode has a forward voltage drop of approximately:

Accepted Answer

0.7 V

Answer

Silicon diodes have a characteristic forward voltage drop (barrier potential) of approximately 0.6–0.7 V.

Question 4

What does the parameter hFE (or β) represent for a BJT transistor?

Accepted Answer

DC current gain (IC/IB)

Answer

hFE (β) is the DC current gain, defined as the ratio of collector current to base current in a BJT.

Question 5

Which biasing configuration for a BJT provides the most stable Q-point against temperature variations?

Accepted Answer

Voltage-divider bias

Answer

Voltage-divider bias sets the base voltage independently of β, making the Q-point very stable over temperature and device variation.

(CET) Certified Euthanasia Technician Practice Test