79xx is a widely known series of low-cost, fixed-negative-voltage regulators. These integrated circuits are available with output current of 100-150 mA (L series), 0.4-0.5A (M series), up to 1A (standard series), etc. They can be used in many applications other than regulators, audio power amplifier being one of them. As shown in the circuit diagram, a simple stereo audio amplifier is built around two 7905 negative-voltage regulators (IC1 and IC2) and a few discrete components. The 7905 IC (a -5V regulator) used here is readily available. However, the circuit will also work with other 79XX regulators if appropriate power supply is used. Both channels shown in the diagram are identical. Hence the description below is only for the first channel. The quality of the output signal is within acceptable limits. Stereo Power Amplifier Using IC 7905 Circuit diagram : . Stereo Power Amplifier Circuit Diagram Regulator IC 7905 works as an amplifier for the voltages applied to common...