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 was found in the May 1959 Radio Electronics magazine. Its purpose is to provide bias...
In the figure we have a circuit that fires from a positive pulse of short duration applied to its...
We found this alarm in a 1992 documentation. The circuit has several timings and the relay can...