This sequential tone generator circuit was found in the July 1980 issue of Radio Electronics magazine. It uses well-known integrated circuits. The tones are generated by programming resistors.
This circuit, obtained in an old publication, causes a second telephone bell to be played in a...
This small transmitter sends signals to the 7 MHz band, but can be modified to operate at other...
This configuration similar to many of this site was found in 1965 General Electric documentation. Modern...