Why class b power amplifiers are more efficient than class a?

Class B power amplifiers are more efficient than Class A amplifiers because they conduct current for only half of the input signal cycle, typically 180 degrees. This reduced conduction time minimizes power dissipation in the form of heat, resulting in higher overall efficiency—often around 50% to 78%. In contrast, Class A amplifiers conduct throughout the entire signal cycle, leading to significant heat generation and typically lower efficiency, around 20% to 30%. Consequently, Class B amplifiers are preferred in applications where power efficiency is crucial.