Bipolar transistors

Which distortion tends to occur in a class B push-pull amplifier in which NPN and PNP transistors handle the positive and negative half-cycles?

  1. AQuantization error
  2. BAliasing
  3. CCrossover distortion
Show answer and explanation

Answer: C. Crossover distortion

In a class B push-pull circuit, when the input is near zero, neither transistor has enough base-emitter voltage to conduct, so the waveform is distorted where the transistors hand over. This is crossover distortion, which is reduced by class AB operation with a small bias current.

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