Power Amplifier Classes
Class A, B, AB, C and D amplifiers trade linearity against efficiency.
Intermediate
| Class | Conduction angle | Max efficiency | Notes |
|---|---|---|---|
| A | 360° | 25 % (50 % with transformer) | most linear, very hot |
| B | 180° per device | 78.5 % () | crossover distortion |
| AB | slightly over 180° | ~50–70 % | standard audio amp |
| C | < 180° | > 80 % | RF only, needs a tuned load |
| D | switching (PWM) | > 90 % | modern audio, needs output filter |
Class D amplifiers (e.g. PAM8403, TPA3116) switch at hundreds of kHz and use an LC filter to recover the audio — efficient enough to need no heatsink.
Spotted a mistake or want to add detail? Suggest an improvement — Content Contributors' edits are reviewed by editors before they go live.
Discussion (0)
Sign in or join free to ask questions and discuss this topic.