(i) The circuit efficiency of a class-B push-pull amplifier is much higher than class-A amplifier.The reason for this is that no power is drawn from the D.C.power supply Vcc under no signal condition in class-B push-pull amplifier.
(ii) The use of push-pull system in the class-B amplifier eliminates even order harmonics in A.C. output signal.
(iii) For a given amount distortion the circuit provides more output per device because of the absence of even harmonics.
(iv) There is no D.C. component in the output signal.It is because of the fact,that D.C. components of two collector currents,through the two halves of primary of the output transformer flow in opposite directions.As a result,there is no possibility of core saturation of the output transformer, even at the peak value of the signals.Thus,we can use smaller sized cores in the transformers,without affecting the circuit performances.
(i) Harmonic distortion is high.
(ii) Self-bias is not used.