COMPLETE RADIO SET PUT IN HEADPHONES (Jul, 1933)
COMPLETE RADIO SET PUT IN HEADPHONES
Inventive ingenuity has succeeded recently in building a complete radio set into a pair of headphones. No batteries’ are required, since the set uses a crystal detector, which is adjusted by manipulating a small knob on one of the receivers, as shown above. To tune in any station, the user has merely to turn a larger knob at the back of the same receiver, operating a diminutive tuning condenser. The set will operate successfully wherever the cords of the set may be plugged into a convenient aerial and necessary ground connections are possible.