A type of amplifier design. Push-Pull is a term that originated in the days of tube amplifiers (which are now having a resurgence). In this design two output tubes are connected in such a way that while the current in one is increasing, it is decreasing in the other. The two signals are then combined in an output transformer and passed on to the load (speakers). The modern solid-state version of this is known as the Complementary Symmetry Circuit (though most lay people still call it push-pull), where two transistors operate in a similar fashion. There are several classes of operation of push-pull designs that we will discuss in upcoming weeks.