This primitive solar radio was found in a Gernsback publication from 1960. The transistor is made of germanium of the time and the earphone is magnetic with high impedance.
This circuit was found in an American publication from the 1980s. In the original version it...
This circuit is from an American documentation of the 1980s. The circuit can be implemented with more...
This is a diagram of a 1958 commercial receiver. The circuit was found in documentation at the...