This 4-tube counter was found in Radio Electronics magazine from December 1959. The circuit uses a coil as a sensor to detect the passage of metallic parts or magnets.
This tone-modulated transmitter was found in recent English documentation. The circuit operates in the 27...
This simple CMOS digital game was found in an English publication in 1992. The circuit uses a...
This good quality stereo amplifier was found in a Japanese publication from the 1960s. The circuit...