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.
Written in an article in Radio Electronics magazine in April 1987, this circuit triggers an alarm...
This circuit was found in the April 1993 Electronics Now magazine. With it, it is possible to...
This circuit was obtained in a1969 magazine. The magazine no longer exists, but the circuit can be...