The Miller effect in a common-emitter BJT amplifier causes:

The correct answer is B: Effective multiplication of base-collector capacitance by (1+Av) at input. Miller effect: CBE capacitance reflected to input = CμC·(1+|Av|); dominates high-frequency response and limits bandwidth in CE configuration.

In a complex digital system, what does 'Setup time' refer to?

The correct answer is B: Minimum time data must be stable before clock edge. Setup time is the minimum duration that the input data must be stable and valid before the active clock edge arrives at the flip-flop.

What is the output frequency of a 4-bit ripple counter when driven by a 16 MHz clock?

The correct answer is D: 1 MHz. In a 4-bit ripple counter, the output frequency of the last stage is f_clock / 2^4 = 16 MHz / 16 = 1 MHz.

In a two-stage RC coupled amplifier, why is a coupling capacitor used between stages?

The correct answer is A: To block DC component of previous stage, passing only AC signal. Coupling capacitors block DC bias from one stage to the next, preventing Q-point shifts. They allow AC signal passage while maintaining proper biasing independently in each stage.

An even signal x(t) has Fourier transform X(f). What can be said about X(f)?

The correct answer is B: X(f) is real and even. For an even signal, the Fourier transform is real and even: X(-f) = X(f) and X*(f) = X(f).

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Electronics (ECE)
Electronic Devices

Analog/digital electronics, communication

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Difficulty: All Easy Medium Hard 41–41 of 41

Topics in Electronics (ECE)

All Electronic Devices 100 Digital Electronics 100 Analog Circuits 100 Signals & Systems 100

Q.41 Medium Electronic Devices

Which parameter is most important for selecting a heat sink for a power transistor?

A Color of the heat sink

B Thermal resistance (θJA)

C Weight of the heat sink

D Cost of the heat sink

Correct Answer: B. Thermal resistance (θJA)

EXPLANATION

Thermal resistance θJA (junction to ambient) determines how effectively heat is dissipated. Lower θJA values indicate better heat dissipation capability, essential for power dissipation calculations: Tj = Ta + (P × θJA).

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Electronics (ECE) Electronic Devices

Electronics (ECE)
Electronic Devices