This circuit was found in an old American publication. The transformer is the type of output found in old transistor radios. The transducer is crystal headphone.
This circuit is used in transceivers, enabling input selection by diode switching through polarity...
This configuration was found in an American publication from the 90s. Operators admit equivalents just...
This circuit was found in an Italian magazine Elettronica Prática of 1977. The transistors can be...