This two-tube circuit, one being a double, was found in Radio Electronics magazine from July 1958. The distance to the microphone depends on noise and losses. The cable must be shielded.
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...