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.
We found this circuit in a Popular Electronics from the 80s. This circuit eventually doesn't work with...
This traditional high sensitivity voltmeter circuit using a FET can employ the MPF102 or BF245 in its...
This circuit operates at a voltage of 1.3 V from a single mercury cell. We found in an old...