We found this circuit in a 1965 publication by General Electric. The zener is 8.2 V x 1 W and the table shows the capacitor values according to the number of cylinders in the vehicle.
This circuit was suggested by Motorola's 1993 Linear Interface ICs. Equivalent operational amplifiers...
This timer, from an old American publication, uses indicator lamps, but can be modified to use...
This low-pass circuit was found in the December 1990 issue of Radio Electronics magazine. The...