BEE Bachelor of Electrical Engineering Semiconductor Devices and Electronics Questions and Answers Flashcards

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

Answer: Voltage regulation

A Zener diode operates in reverse breakdown to maintain a constant voltage across its terminals, making it ideal for voltage regulation.

In a MOSFET, what does the threshold voltage (Vth) represent?

Answer: The minimum gate-to-source voltage needed to create a conducting channel

The threshold voltage is the minimum gate-to-source voltage required to form an inversion layer and create a conductive channel between source and drain.

Which semiconductor material has a bandgap energy of approximately 1.12 eV at room temperature?

Answer: Silicon

Silicon has a bandgap energy of approximately 1.12 eV at 300 K, which is fundamental to its widespread use in electronics.

What phenomenon causes the collector current in a BJT to increase slightly with increasing collector-emitter voltage in the active region?

Answer: Early effect

The Early effect (base-width modulation) causes the effective base width to narrow as VCE increases, slightly increasing collector current.

In a p-n junction, what is the built-in potential primarily caused by?

Answer: Diffusion of carriers across the junction creating an electric field

The built-in potential arises from carrier diffusion across the junction, which creates a depletion region and an internal electric field that opposes further diffusion.

What is the main advantage of a CMOS inverter compared to an NMOS-only inverter?

Answer: Near-zero static power dissipation

CMOS inverters have near-zero static power dissipation because one of the two transistors is always off in either logic state, preventing a direct path from supply to ground.