This circuit is suggested by National Semiconductor in its Linear Applications Handbook. The LM3909 integrated circuit consists of a very low consumption oscillator with a power supply of 1.2 V.
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....