Which amplifier class is most associated with crossover distortion?

• A. Class A
• B. Class AB
• C. Class C
• D. Class B

Answer: (D)

Crossover distortion shows up when the output stage of a push-pull amplifier has a dead region near zero where neither device conducts. In Class B, each transistor conducts only for half of the waveform and is biased at cutoff, so as the signal crosses zero there’s a brief gap where neither transistor is on. That creates a noticeable kink in the output, the classic crossover distortion. If you bias a little more to keep both devices conducting around the zero-crossing (Class AB), the distortion is reduced. Class A avoids this issue entirely because both devices are on all the time, but with poor efficiency, and Class C conducts for less than 180 degrees and is not used for audio due to overall heavy distortion. So the type most associated with crossover distortion is Class B.