Based on the 4017 integrated circuit, this circuit of a European 303 Circuits from the 90s, generates a pulse train in a relay that mimics the dialing of a telephone.
This circuit was found in an old documentation and can be powered by a solar panel. The touch...
This circuit was obtained from 1967 documentation. It uses a sensor to determine the trigger...
This sophisticated logic probe for 5 to 12 V circuits (CMOS and TTL) was found in a 1980s...