This circuit was originally recommended to give the call signal on intercoms. However, it can be used with other applications. The circuit is from 1978 documentation. The transistor may be the BC548.
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...