Found in a 1980s documentation, this circuit works with a 12V relay. The horn is the boat's own.
This 6V microsupply with just 2mA current uses a common 1N34 germanium diode. The circuit was...
This electronic siren circuit, found in a 1982 documentation, uses three oscillators mounted...
This integrated circuit is recommended as a standard amplifier in sound equipment, TV sets,...