Make Pt1679
Listeners Applaud Program Modern Mechanix, 1937 –

BY PRESSING an electric switch, radio listeners may express approval of a current radio program. Holding down a small switch attached to the base of a small lamp placed near the radio, the increased current drain is shown at the local power plant or substation.

Now being used in France, the idea was first tried out by an American power company working with an eastern broadcasting chain.