Found in an old publication, this is a transmitter with a spark coil. The high frequency oscillations of the high voltage spark generate the signal thrown at the antenna.
Found in a 1990s American technical brochure, this circuit is intended for alarms that use as...
This control for bass, midrange, and treble was found in the March 1995 issue of Electronics Now...
Found in a 1965 General Electric documentation, this circuit is intended to control a 150 W lamp...