This amplifier circuit with a low power MOSFET was found in Popular Electronics from the 90s. The circuit uses a small transformer of the type found in old transistor radios.
This circuit uses a Hall device from that time as a sensor. The circuit is from an English...
Found in Radio Electronics from the 90s, this siren finds many variations on this site. The...
This audio generator that produces both rectangular and sinusoidal signals was found in a...