This automotive circuit was obtained from an 80's schematic from the integrated circuit factory itself. The voltage regulator is still common, but the operational amplifier is of the time.
This is a configuration much explored by assemblers, being found on this site in dozens of similar...
This circuit was obtained in an old English magazine (TSI) 1998 and consists of a Schmitt trigger...
This circuit is from an 80's publication. It makes use of small 6 V x 50 mA incandescent lamps....