This circuit makes use of comparators and common operational amplifiers, having been found in Motorola Linear Interface ICs of 1993. The circuit requires symmetrical source.
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...