This is one of the many versions we have of a 12 V power supply with the 7812. We found it in the Radio Electronics magazine of July 1984. The integrated circuit must be mounted on a heat sink.
We find this circuit in an American 80's documentation. It makes use of IC sensor which is mounted...
This is a configuration obtained from an old manual, using an operational amplifier of the time....
In the figure we have the way to add hysteresis to an operational amplifier. The relationship...