The Definition of a Breadboard Radio

Early Electrical Manufacturing

• Arthur Atwater Kent started the Kent Electrical Manufacturing Co. in 1895. The company originally made motors and fans in Philadelphia. By 1902, the company was making small electrical devices, automotive components, and by the 1920s, radios. Early Atwater Kent radios were constructed on planks of wood that became known as "breadboards." Later, Atwater Kent radios were made in chassis to fit cabinets produced by early manufacturing companies.

Origin of Term &'Breadboard&'

• It is unclear whether Kent Manufacturing used the term "breadboard" for the platform of its early radios or if amateur radio operators "borrowed" actual breadboards from their own kitchens and Kent later adopted the process and the term for radio manufacture. Early breadboard radios, whether homemade or manufactured, continue to be prized by collectors and command high prices. The term "breadboard" lives on as a mounting platform for electrical circuits.

Breadboard Receivers

• Atwater Kent&'s tuned radio frequency receiver (TRF), as Kent Manufacturing&'s early radios were called, were assembled by the buyer who ordered individual components from the company and put them together at home. The model 3925 (also known as the Model 1) was introduced in 1922 and had a tuner, detector and one-stage amplifier. The set had two tubes. By 1924, when the last Atwater Kent breadboard radio was shipped, a six-tube Model 12 with various component refinements had been introduced.

Early Breadboard Radio Design.

• The first tube circuits were built on a wooden board (breadboard). The tube sockets were surface-mounted, using wood screws. Tie points were attached to the board to secure resistors and capacitors. Open-frame transformers were then attached to the wooden surface. The result was a tuned radio-frequency receiver composed of radio-frequency amplifiers followed by electrical circuits to detect and amplify the signal.

Later Developments

• The breadboard radio construction was eventually replaced by plastic circuit boards mounted to the bottom of a wooden box with a hinged wooden top. The front panel, containing variable capacitor controls and jacks, were then mounted to the front surface of the box. Conductors became sheet metal strips riveted to the board rather than traces bonded directly to the plastic. The breadboard radio had thereby given way to an early form of cabinet radio.