Amplifiers: types and basic principles MCQs January 8, 2026November 19, 2024 by u930973931_answers 20 min Score: 0 Attempted: 0/20 Subscribe 1. The main purpose of an amplifier is to: (A) Convert AC to DC (B) Filter signals (C) Convert low frequencies to high frequencies (D) Amplify the amplitude of a signal 2. The amplifier class that has the highest efficiency is: (A) Class A (B) Class D (C) Class AB (D) Class B 3. In an amplifier, the gain is defined as the ratio of: (A) Input power to output power (B) Output signal to input signal (C) Output power to input signal (D) Input voltage to output current 4. The ideal gain of an amplifier is: (A) Zero (B) Infinite (C) One (D) 1000 5. Which type of amplifier is typically used in audio systems to increase the volume of sound? (A) Power amplifier (B) Differential amplifier (C) Operational amplifier (D) Voltage amplifier 6. In a class A amplifier, the output transistor conducts: (A) For half of the input signal (B) Continuously for the full cycle of the input signal (C) For a quarter of the input signal (D) Only for the positive half-cycle of the input 7. The main disadvantage of a class A amplifier is: (A) High distortion (B) Low efficiency (C) Low power gain (D) High efficiency 8. A class B amplifier is characterized by: (A) Amplifying the entire input signal (B) Amplifying only the positive half of the input signal (C) Amplifying only the negative half of the input signal (D) Amplifying half of the input signal with two transistors, one for positive and one for negative half 9. Which of the following amplifiers is known for producing minimal crossover distortion? (A) Class A amplifier (B) Class AB amplifier (C) Class B amplifier (D) Class D amplifier 10. A class D amplifier is often used in: (A) Both high-power audio and efficient power supplies (B) Low-power applications (C) Digital signal processing (D) High-power audio amplification 11. In a common-emitter amplifier, the input is applied to the: (A) Collector (B) Emitter (C) Base and emitter (D) Base 12. In a common-collector amplifier (also called an emitter follower), the output is taken from the: (A) Base (B) Collector (C) Emitter (D) Ground 13. A common-base amplifier has a voltage gain that is: (A) Zero (B) Less than 1 (C) Equal to 1 (D) Greater than 1 14. The primary function of a differential amplifier is to: (A) Amplify the difference between two input signals (B) Amplify a single input signal (C) Amplify both input signals equally (D) Convert AC signals to DC 15. In an op-amp based non-inverting amplifier, the input signal is applied to the: (A) Non-inverting input (B) Inverting input (C) Output terminal (D) Both inverting and non-inverting inputs 16. The primary application of an operational amplifier (op-amp) is in: (A) Oscillator circuits (B) Voltage regulation (C) Amplifying weak signals (D) Power supply design 17. Which of the following amplifiers is typically used in radio-frequency (RF) circuits? (A) Voltage amplifier (B) Power amplifier (C) High-frequency amplifier (D) Transistor amplifier 18. A low-noise amplifier (LNA) is used to: (A) Amplify high-frequency signals without significant noise (B) Reduce the noise of an audio signal (C) Increase power efficiency (D) Provide high-gain amplification in power circuits 19. Which of the following is an application of a buffer amplifier? (A) Increasing the voltage of a signal (B) Converting AC to DC (C) Matching impedances between circuits (D) Decreasing the power output of a signal 20. A power amplifier is used in applications requiring: (A) Voltage amplification (B) Low distortion (C) Signal filtering (D) High-current output