Question

Which of the push-pull amplifiers is presently the most popular form of the class B power amplifier?

(a) Quasi-complementary

(b) Transformer-coupled

(c) Complementary-symmetry

(d) Symmetry

The question was posed to me during an interview for a job.

This is a very interesting question from Classification of Output Stages in section Differential and Multistage Amplifiers of Electronic Devices & Circuits

Answer 1

The correct choice is (a) Quasi-complementary

For explanation: In class B operation, a push-pull connection is obtained using either a transformer coupling or by using complementary (or quasi-complementary) operation with npn and pnp transistors to provide operation on opposite polarity cycles. While transformer operation can provide opposite cycle signals, the transformer itself is quite large in many application.