This circuit for automotive use was found in American documentation from the 90s. The circuit uses common components today. The relay is 12 V.
This is the basic configuration of an operational amplifier sample & hold circuit. The FET and...
The integrated circuit 4136 consists of operational amplifiers of type 741 in the same enclosure and...
We find this circuit in a 1987 publication. It makes use of comparators constructed around the 741...