This adjustable circuit from 0 to 200 nA was found in a 90's EDN. The components can still be found relatively easily, as they are CMOS.
This circuit, from a 1988 publication, consists of a timer that activates a relay at the end of a...
Found a documentation for PC from 1992, this circuit is indicated for the English power grid of...
This conventional window comparator configuration was found in an old documentation. It is valid...