This current switch was found in a Radio Electronics from November 1957. It triggers the current determined by the electromechanical sensor, a polarized relay of the time.
This circuit is from an old publication from the 70s, but it can be implemented with more modern...
This circuit was found in an American 80s circuit manual. The components used are unusual. The...
We found this circuit in a 1976 documentation. The transistor and the integrated circuit must have...