Why are switching amplifiers more efficient than linear amplifiers?

Switching amplifiers (such as Class D, E, or F) achieve high efficiency because their transistors act as electronic switches. They rapidly alternate between being fully on (saturation) and fully off (cutoff). When a transistor is fully on, it has almost no voltage drop across it, resulting in near-zero power dissipation. When fully off, no current flows, which also means near-zero power dissipation. In contrast, linear amplifiers (like Class A or AB) operate in the active region where significant voltage and current are present in the transistor simultaneously. This continuous state dissipates much more power as heat, lowering overall efficiency. Distractors like push-pull circuits or operating voltages do not inherently define switching amplifier efficiency.