This 4-tube counter was found in Radio Electronics magazine from December 1959. The circuit uses a coil as a sensor to detect the passage of metallic parts or magnets.
This circuit is from 1964 documentation but can be easily implemented based on current components....
This circuit was obtained in an English publication of 1975. It is a circuit that stabilizes an...
We found this circuit in the April 1975 Radio Electronics magazine. The circuit has a latch and...