This power supply protection circuit using a relay was found in a 1967 documentation. The components are from the time, but current equivalents can be used depending on the power source current.
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...