Found in 90s Radio Electronics, this shield can control high voltage loads in the power grid. Isolation is guaranteed by the use of an optical coupler.
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...