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.
This is one of the many hysteresis comparator circuits the reader may find in this section and on this...
This circuit is from a Radio Electronics from February 1971. The SCR is load controlled and the...
Found a documentation on PCs from 1996, this circuit can be used as a shield. The relay is rated at...