ISCET Semiconductor Devices 2

Question 1

What is the primary function of the depletion region in a reverse-biased PN junction?

Accepted Answer

To act as an insulating barrier that blocks majority carrier flow

Answer

The depletion region widens under reverse bias, creating an effective insulating barrier that prevents majority carriers from crossing the junction.

Question 2

A Zener diode is operating in reverse breakdown at 6.2 V with 20 mA flowing through it. What is the power dissipated?

Accepted Answer

0.124 W

Answer

Power = V × I = 6.2 V × 0.020 A = 0.124 W.

Question 3

Which BJT configuration provides the highest voltage gain but has a current gain less than 1?

Accepted Answer

Common base

Answer

The common-base configuration has a current gain (alpha) slightly less than 1 but can provide significant voltage gain.

Question 4

In an N-channel JFET, pinch-off voltage (Vp) is the gate-to-source voltage at which:

Accepted Answer

The channel is fully depleted and drain current drops to nearly zero

Answer

Pinch-off voltage is the negative VGS value that fully depletes the N-channel, reducing drain current (IDSS) to essentially zero.

Question 5

Which parameter describes the ratio of the change in collector current to the change in base current in a BJT?

Accepted Answer

Beta (β)

Answer

Beta (β or hFE) is defined as IC/IB and represents the DC current gain of a BJT in common-emitter configuration.

(ISCET) International Society of Certified Electronics Technicians Practice Test