Found in old documentation as permanent security lighting, this circuit uses common components. The lamps can be replaced by fluorescent inverters or LEDs with appropriate series resistors.
The integrated circuit used in this project is not common today, but it can be implemented with more...
Found in an American publication from 1969, this circuit can be adapted to be used as a shield....
This current meter with many scales was found in a 80s American documentation. The operational amplifier...