This simple receiver of two transistors for the 80-meter range was found in an American documentation from the 1980s. The transistors admit equivalents and the antenna must be long.
Incandescent lamps and heaters can be controlled by a low power switch using this circuit. The...
August 2016 - It can be found at Mouser Electronics the new sensors light to digital OPT3002 from...
This alarm uses several sensors that directly trigger a sensitive relay. A larger relay can be...