This 555-based circuit was found in the August 1976 issue of Radio Electronics magazine. The tone frequencies are provided by the capacitors connected to the 555 IC.
This circuit has an interesting application. If a device with the selector switch in the 110 V...
This simple radio circuit was obtained in a Japanese publication in 1967. The circuit uses...
This circuit was found in a Popular Electronics from the 90's. The components used are common and...