ISCET - International Society of Certified Electronics Technicians Semiconductor Device Principles Questions and Answers

Question 1

In a P-N junction diode, what is the primary reason for the formation of the depletion region?

Accepted Answer

Recombination of majority carriers near the junction

Answer

Application of an external reverse bias voltage

Answer

Thermal generation of electron-hole pairs

Answer

The flow of minority carriers across the junction

Question 2

A technician is testing a component and finds that it is a voltage-controlled device with a very high input impedance. Both majority and minority carriers are NOT involved in its operation. Which of the following devices is it most likely to be?

Accepted Answer

A Field-Effect Transistor (FET)

Answer

A Zener Diode

Answer

A Bipolar Junction Transistor (BJT)

Answer

A Silicon Controlled Rectifier (SCR)

Question 3

What is the effect of applying a forward bias voltage to a P-N junction that is greater than the barrier potential?

Accepted Answer

The depletion region narrows, and significant current begins to flow.

Answer

The depletion region widens, and current flow is blocked.

Answer

The number of minority carriers increases, causing avalanche breakdown.

Answer

The resistance of the junction increases exponentially.

Question 4

Which of the following describes the operating principle of an N-channel enhancement-mode MOSFET (E-MOSFET)?

Accepted Answer

The device requires a positive gate-source voltage (Vgs) to create a conductive channel and turn ON.

Answer

A negative gate-source voltage (Vgs) is required to deplete a pre-existing channel and turn the device OFF.

Answer

The device is normally ON at Vgs = 0, and a negative voltage enhances the channel.

Answer

Current flows from drain to source regardless of the gate voltage.

Question 5

A technician needs to select a transistor for a high-frequency switching application where low power consumption is critical. Which of the following would be the most suitable choice?

Accepted Answer

A Field-Effect Transistor (FET) due to its high input impedance and faster switching speed.

Answer

A Bipolar Junction Transistor (BJT) due to its high gain.

Answer

A thyristor, because it can handle high power.

Answer

A phototransistor for its light-sensing capabilities.

Question 6

The process of adding impurities like phosphorus or boron to an intrinsic semiconductor like silicon is known as:

Accepted Answer

Doping

Answer

Recombination

Answer

Diffusion

Answer

Annealing