Based on a CA3059 zero-cross switch, this circuit was found in the July 1995 Electronics Now magazine. The circuit is not isolated from the mains.
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...