This circuit was suggested by National Semiconductor and is present elsewhere on this site. The LM2575 is not very common today and should be mounted on a heatsink.
Found in 90s Popular Electronics, this circuit fires a load through a MOSFET from an audio signal...
Found in Radio Electronics from the 90s, this circuit uses components from that time. However, it...
This automatic volume control for audio signals was found in American documentation from the 90s....