Found in an old Popular Electronics, this circuit warns when a remote lighting system is not working. The circuit uses an LDR as a sensor and the components used are quite common today.
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...