Feedback amplifier system with transformer secondary output - obtains feedback signal from auxiliary transformer primary and passes it to inverting input of operational amplifier

摘要

The amplifier has its feedback signal independent of the earth connection in its output circuit. The feedback signal is obtained using an auxiliary transformer connected to the output by its primary winding. The feedback signal is passed via a voltage divider to the inverting input of an operational amplifier connected to the input side of the amplifier. The input signal (1) is applied to the operational amplifier non-inverting input and via the voltage divider (7, 8) to the inverting input. The operational amplifier output is connected via a power amplifier (3) to the primary of the output transformer (5), whose secondary feeds the load (4) and is coupled to the auxiliary transformer (6) primary.