Electronics (ECE) - MCQ Practice Questions

A BJT amplifier exhibits thermal runaway due to increased leakage current. Which design modification can best prevent this phenomenon?

In a Common Emitter amplifier, if the input impedance is 1 kΩ and the output impedance is 50 kΩ, what is the approximate voltage gain if β = 100 and gm = 0.04 S?

An inverting amplifier using op-amp has Rf = 100 kΩ and Rin = 10 kΩ. What is the voltage gain magnitude?

Which configuration provides the highest input impedance and lowest output impedance among op-amp circuits?

In a Hartley oscillator, the frequency of oscillation is determined by which circuit element combination?

For the oscillator to sustain oscillations, the loop gain must satisfy which condition (assuming phase shift is 360° or 0°)?

A Class B amplifier has two transistors operating in push-pull configuration. What is the maximum theoretical efficiency?

In a differential amplifier, Common Mode Rejection Ratio (CMRR) is measured as 80 dB. What is the numerical ratio of differential gain to common mode gain?

Which type of feedback is applied in a non-inverting amplifier configuration?

For an ideal op-amp, the input offset voltage is:

In an RC phase shift oscillator, how many RC sections are typically used to achieve 180° phase shift?

A feedback amplifier with closed-loop gain Acl = 10 has feedback fraction β = 0.1. What is the open-loop gain (A)?

The Miller effect in a Common Emitter amplifier results in:

In a Wein bridge oscillator, the frequency of oscillation is given by f = 1/(2πRC). At what condition does oscillation start?

A transistor amplifier has input signal of 10 mV and output signal of 5 V. What is the voltage gain in dB?

In a transimpedance amplifier (TIA), which parameter determines the transimpedance gain?

Which oscillator topology has the poorest frequency stability due to dependency on passive component tolerances?

A power amplifier delivers 100 W to a 8 Ω load. What is the RMS output voltage? (Assuming pure resistive load)

In a two-stage amplifier with individual gains A₁ = 50 and A₂ = 100, if negative feedback β = 0.01 is applied across both stages, what is the approximate closed-loop gain?

For maximum power transfer from a source to load through an amplifier, what should be the relationship between source and load impedance?