Basic Complementary (Push-Pull) Power Amplifier Circuit

This amplifier circuit is very popular audio power amplifier circuit type. We call it a complementary since the final transistors is an NPN-PNP pair, each with the same characteristics. This circuit produce an AB class amplifier, since each transistor works in slightly more than half cycle of the signal. There is overlap area when both transistor conduct a current, and this area will be around its stationary current (when the input signal is zero). This circuit is also known as push-pull amplifier circuit since each transistor in the pair is working alternatively. Here is the schematic diagram of the circuit: