This 4-tube circuit was found on a Radio Craft from December 1945. The circuit has excellent sensitivity. Power comes from a power supply with a transformer.
This 1 A circuit was found in a Philips documentation from 1966. The transistor is of the time,...
We found this circuit in a Popular Electronics of the 90s. The circuit can also be used as a seat...
This two-digit timer was found in the 1983 Special Projects issue of Radio Electronics magazine. The...