Audio amplifier circuit using operational amplifiers - has capacitors coupling outputs of subtractor and inverter amplifier to inputs of opposite amplifier to provide symmetrical characteristic

摘要

The circuit has an operational amplifier (XS1) acting as a subtractor and a second operational amplifier (XS2) acting as an inverter. The output (3) of the first amplifier is coupled to the inverting input (5) of the second amplifier. The output (6) of the latter is coupled to the non-inverting input (2) of the first amplifier, which is coupled to earth via a capacitor (C2). Respective capacitors (C1, C3, C4) provide a feedback signal between the output (3) of the first amplifier and its inverting input (1) and couple the amplifier outputs (3, 6) to the inverting and non-inverting inputs (5,2) of the opposite amplifier. ADVANTAGE - Ensures constant symmetry characteristic of audio amplifier over audio frequency range.