This circuit is from an old American documentation from the 70s. Transistor 2N3904 can be replaced by BC548. The relay must have 100 mA of maximum current.
The purpose of this simple stabilized source, obtained in a documentation from the 70s, is to...
This simple receiver for listening on a crystal phone tunes the range of medium waves. The circuit...
This medium- or short-wave receiver circuit was found in documentation from the 1980s. The circuit...