This midrange filter for sound systems was found in the May 1988 issue of Radio Electronics magazine. The circuit is based on a dual amplifier that must be powered by a symmetrical source.
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...