This circuit is from Motorola's Linear Interface ICs from 1993. The MC1723 is the equivalent of the well-known 723. The transistor supports equivalents.
Found in American documentation from 1968 this circuit is based on discrete components in addition...
This simple circuit indicates, through an LED, when the water level of a filter (or other kind of...
This circuit appears in similar versions elsewhere on this site. The transformer is 110 V or 220 V...