This circuit was found in Philips documentation from 1967. The components are of the time, being transistors like BCY38 for TR1, BC108 for TR3, and others depending on currents.
This circuit was found in an ancient American documentation. The integrated circuit is of the time...
This circuit turns on a lamp when the night comes and turn it off in the morning. The circuit...
This circuit is from an Electronics World of 1967. The described calculations can be applied to...