ISCET Semiconductor Device Principles 2

Question 1

What is the primary effect of increasing temperature on the reverse saturation current (I₀) of a silicon diode?

Accepted Answer

I₀ approximately doubles for every 10°C rise

Answer

I₀ decreases exponentially

Answer

I₀ remains constant

Answer

I₀ decreases linearly

Question 2

In a PNP bipolar junction transistor operating in active mode, the emitter current is 10 mA and the base current is 0.2 mA. What is the collector current?

Accepted Answer

9.8 mA

Answer

10.2 mA

Answer

0.2 mA

Answer

50 mA

Question 3

Which semiconductor parameter defines the average time a minority carrier exists before recombining?

Accepted Answer

Minority carrier lifetime

Answer

Mobility

Answer

Diffusion length

Answer

Transit time

Question 4

A Zener diode is used primarily in which region of its V-I characteristic?

Accepted Answer

At the Zener breakdown voltage

Answer

Forward bias above 0.7 V

Answer

Reverse bias below the breakdown voltage

Answer

In the depletion region only

Question 5

What is the typical value of the Early voltage (VA) for a small-signal BJT, and what does a larger VA indicate?

Accepted Answer

Typically 50–200 V; larger VA means higher output resistance and less channel-length modulation

Answer

Typically 5–10 V; larger VA means more output resistance variation

Answer

Typically 0.7 V; larger VA means the transistor saturates sooner

Answer

Typically 1 kV; larger VA means lower gain

Question 6

In an N-channel JFET, what happens to the drain current when the gate-to-source voltage (VGS) is made more negative?

Accepted Answer

Drain current decreases toward zero

Answer

Drain current increases

Answer

Drain current remains constant

Answer

Drain current reverses direction

Question 7

Which effect describes the increase in BJT collector current due to base-width narrowing as VCE increases?

Accepted Answer

Early effect

Answer

Miller effect

Answer

Punch-through effect

Answer

Kirk effect