CET Semiconductor Devices & Circuits 4

Question 1

In a transistor amplifier, the quiescent point (Q-point) represents:

Accepted Answer

The DC operating point with no AC signal applied

Answer

The Q-point defines the DC bias conditions (VCE, IC) at which the transistor operates before any AC signal is applied.

Question 2

What is the primary advantage of a Darlington pair transistor configuration?

Accepted Answer

Very high current gain (β1 × β2)

Answer

A Darlington pair cascades two BJTs so the combined current gain is approximately the product of both individual gains.

Question 3

Which parameter defines the maximum safe operating temperature junction for a semiconductor device?

Accepted Answer

TJ(max)

Answer

TJ(max) specifies the maximum allowable junction temperature, beyond which the device may suffer permanent damage or failure.

Question 4

In a class-A amplifier, the transistor conducts for:

Accepted Answer

360° of the input cycle

Answer

Class-A amplifiers bias the transistor to conduct for the entire 360° of the input waveform, providing low distortion but low efficiency.

Question 5

The Early effect in a BJT refers to:

Accepted Answer

Modulation of the effective base width by collector voltage

Answer

The Early effect (base-width modulation) describes how increasing VCE narrows the base width, slightly increasing collector current.

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