This circuit was found in an old documentation for radio amateurs. The circuit makes use of an uncommon integrated today. The circuit converts telegraph signals to be used on the computer.
This simple metronome, from 1985 documentation uses only transistors and has two settings. For...
This circuit is suitable for modulating AM transmitters. The circuit is from a 1977 radio amateur...
This flasher was found in an old Hands On, but uses common components. The optocoupler can be...