ISCET Semiconductor Devices 5

Question 1

A Schottky diode differs from a standard PN junction diode primarily because it:

Accepted Answer

Forms a metal-semiconductor junction with no minority carrier storage, allowing faster switching

Answer

Schottky diodes use a metal-semiconductor junction instead of a PN junction, eliminating minority carrier storage and enabling much faster switching speeds.

Question 2

What does the term 'transconductance' (gm) describe in a FET?

Accepted Answer

The ratio of the change in drain current to the change in gate-source voltage

Answer

Transconductance (gm = ΔID/ΔVGS) measures how effectively the gate voltage controls the drain current, and is the key gain parameter for FET amplifier design.

Question 3

A PIN diode is commonly used in RF applications because:

Accepted Answer

Its intrinsic (I) region provides a voltage-controlled resistance at RF frequencies

Answer

The wide intrinsic layer of a PIN diode acts as a variable RF resistance controlled by DC bias current, making it useful for RF switching and attenuation.

Question 4

When a BJT is in the active (linear) region, which junction biasing condition applies?

Accepted Answer

Base-emitter forward biased; base-collector reverse biased

Answer

Normal active-region operation requires the base-emitter junction forward biased (VBE ≈ 0.7 V for silicon) and the base-collector junction reverse biased.

Question 5

The maximum reverse voltage a diode can withstand without breakdown is called the:

Accepted Answer

Peak Inverse Voltage (PIV) or Peak Reverse Voltage (PRV)

Answer

The PIV (or PRV) rating specifies the maximum reverse voltage a diode can block; exceeding it causes destructive avalanche or Zener breakdown.

(ISCET) International Society of Certified Electronics Technicians Practice Test

(ISCET) International Society of Certified Electronics Technicians Practice Test

ISCET Semiconductor Devices 5