Found in ancient American documentation this circuit uses semiconductors from the thyristor family such as SCRs, Triacs and unijunctions. The circuit can control loads up to 550 W with the indicated triacs.
This 1970 Philips circuit uses a mechanical counter. The circuit is triggered by a reed switch...
By the components used this circuit of old English documentation can still be easily assembled. The...
It can be obtained from Mouser Electronics new tactile keys subminiature SMT KMR 6 Series C & K....