This small tone generator was found in the November 1987 issue of Radio Electronics magazine. The phototransistor is common and controls the sounds generated. The basic frequency is given by C1.
This simple circuit uses a car ignition coil. The circuit appeared in the 1983 Radio Electronics Annual...
Found in Popular Electronics, this sophisticated short-wave receiver requires a lot of skill from...
Found in Motorola documentation from 1967, this circuit shows how it is possible to obtain a...