CET Semiconductor Devices & Circuits 3

Question 1

What is the depletion region in a p-n junction?

Accepted Answer

The region devoid of mobile charge carriers near the junction

Answer

The region where majority carriers accumulate

Answer

The p-type semiconductor bulk material

Answer

The metal contact layer

Question 2

Which of the following describes the operation of an enhancement-mode NMOS transistor when VGS = 0?

Accepted Answer

Channel does not exist (OFF)

Answer

Channel is fully open (ON)

Answer

Channel is partially open

Answer

Device operates in saturation

Question 3

The breakdown mechanism in heavily doped, thin-junction diodes at low reverse voltages is called:

Accepted Answer

Zener breakdown

Answer

Avalanche breakdown

Answer

Thermal runaway

Answer

Punch-through

Question 4

In a common-emitter amplifier, what is the phase relationship between the input and output signals?

Accepted Answer

180° out-of-phase

Answer

In-phase (0°)

Answer

90° leading

Answer

90° lagging

Question 5

A varactor diode is used primarily as a:

Accepted Answer

Voltage-controlled capacitor

Answer

Variable resistor

Answer

Current-controlled inductor

Answer

Fixed voltage reference

Question 6

What is the pinch-off voltage in a JFET?

Accepted Answer

The gate-source voltage that reduces drain current to nearly zero

Answer

The gate voltage at which the drain current is maximum

Answer

The drain voltage where the channel becomes ohmic

Answer

The supply voltage required to turn on the device

Question 7

An SCR (Silicon Controlled Rectifier) can be triggered into conduction by:

Accepted Answer

Applying a positive pulse to the gate

Answer

Reducing anode voltage below threshold

Answer

Reversing the anode-cathode polarity

Answer

Removing the gate signal permanently