Push-pull Amplifier
An amplifier is used to produce the output voltage greater than the input voltage. A push-pull amplifier includes two tubes. Their control grids are connected to the opposite ends of the input transformer secondary winding. The centre of this winding is connected to the tube cathodes. When maximum grid voltage is produced in one tube, minimum grid voltage is produced in the other tube. Thus, the sum of the plate currents remains constant.
The plate currents are fed into the opposite ends of the
output transformer or a choke coil. It has its centre connected through the plate current supply to the cathodes. Thus direct current plate components are eliminated but alternating current components add in the circuit.