Found in a 1968 US publication, this circuit can operate on any power grid. The thickness of the wire depends on the load current.
This circuit is the conventional use of the 7805 as a constant current source up to 1 A. The...
The integrated circuit used in this application is not currently common. The circuit is from an...
This circuit is from a Radio Electronics from February 1966. The circuit is of a type that was...