Which of the following amplifier classes typically offers improved energy efficiency?

Amplifier Class D is known for its improved energy efficiency compared to other classes. This is primarily due to its operation, which involves switching the output devices on and off rapidly, rather than operating in a linear fashion like Classes A, B, and C. In Class D amplifiers, power transistors are either fully on (saturation) or fully off, minimizing the time that they spend in the linear region where heat is generated. This results in significantly less heat production and therefore, higher efficiency rates, often exceeding 90%.

Class A amplifiers run hot and are inefficient since they conduct current constantly, regardless of the input signal. Class B amplifiers improve on this by only allowing current flow during half of the input cycle but still face inefficiencies due to crossover distortion. Class C amplifiers are more efficient than A and B but are primarily used for RF applications and not for audio signals due to their higher distortion levels.

In summary, Class D offers a significant advantage in energy efficiency over other amplifier classes due to its distinctive switching design, making it particularly suited for applications where power conservation is critical.