This automotive grade circuit was found in a 1991 Electronics Hobbyist. The transistors are general purpose types. P1 sets the monitoring voltage.
This circuit is suggested by Texas Instruments and can be used on an assembly line to drive an...
In the figure we have a interfacing circuit of TTL logic as CMOS logic using a 6N139 optical...
This alarm with sensors in series and parallel was found in the 1995 Encyclopedia of Electronic...