Question
What is a Class D amplifier?
Answer Options
- A) An amplifier that uses switching technology to achieve high efficiency
- B) A low power amplifier that uses a differential amplifier for improved linearity
- C) An amplifier that uses drift-mode FETs for high efficiency
- D) An amplifier biased to be relatively free from distortion
Correct Answer: A
Explanation
Amplifier classes A, B, AB, and C are analog, linear amplifier types. Class D is a different architecture altogether, operating outside of the continuous, linear mode. It is primarily used in audio and modern RF power applications where maximum efficiency is paramount.
A Class D amplifier is a digital amplifier that uses switching technology to achieve high efficiency. The input signal is converted into a series of digital pulses, and the active devices (like MOSFETs) operate only as fast switches, alternating rapidly between cutoff (off) and saturation (on). Since the devices spend very little time in the linear region, power dissipation as heat is minimal, leading to efficiencies often exceeding 90%.
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