#Transistor radios 1950s portable

The transistor allowed for the rapid replacement of tubes in two very common electronic devices - hearing aids and portable radios. The properties of the transistor - small size, very long life expectancy, and no filament heater, which meant longer battery life and low heat output - overcame the limitations of the vacuum tube. (United Press photo from the editor's collection.) The device is about half the size of an ordinary paper clip. February 1952 - One of RCA's laboratory technicians gives a final inspection of the strengthened version of its new transistor. In ten years, the transistor had grown from an exciting laboratory prototype to a mass-produced technology which found uses in all kinds of products.įigure 2. In 1955, over 3,500,000 transistors were manufactured, and in 1957 almost 29,000,000 units were made. In 1953, approximately 1,000,000 units were manufactured. For example, see RCA's 'bean-sized' transistor, shown in Figure 2. This new type of transistor was the basis for a large scale increase in the quantities of transistors manufactured by a variety of companies. The junction transistor was constructed using a die or chip of germanium, with transistor action accomplished by any of several different manufacturing techniques, such as adding controlled amounts of impurities to the germanium - the point contacts, with their inherent drawbacks, had been eliminated. This time a new type of transistor, called a 'junction transistor,' also shown in Figure 1, was made public. In July 1951, Bell Labs again made an announcement regarding transistors. This type of transistor was never in widespread commercial production, and found limited usage in the military, such as in the TRADIC airborne digital computer, and in Western Electric telephone switching equipment. 79.)īy mid-1952, Western Electric was manufacturing 6,000 point contact transistors a month. (From 'The Radio Amateur's Handbook' of the American Radio Relay League,1956, p. A simplified illustration of the construction of point-contact and junction-type transistors. By 1951, sufficient progress had been made to overcome some of the limitations of this type of transistor, and commercial production began at the Western Electric plant in Allentown, Pennsylvania.įigure 1. Nevertheless, Bell Labs continued to refine the techniques for point contact transistor development.

While this technique allowed for the discovery of transistor action, the resulting device was not ideally suited for large scale commercial usage - the point contacts were erratic, mechanically unstable and yielded wide ranges of performance. The transistor developed by Bell Labs in 1947 was of the type known as 'point contact.' This term refers to the technique used to attach two fine wires as points of contact to a germanium block, as shown in Figure 1. Although there were working demonstrations of the potential uses of the transistor presented to the audience (audio oscillator, audio amplifier, and radio receiver), no one present could have known or reasonably predicted the tremendous impact that this device would have on technology over the next 50 years. For example, the transistor was small, lightweight, required no vacuum or filament current, and apparently had an unlimited lifetime. The transistor had actually been invented 6 months earlier, December 1947, but the public announcement had been delayed to allow for filing of patents and disclosure to the military.Īt the press conference, this new device was presented as an equivalent of the vacuum amplifier, except that it had desirable properties which overcame some of the fundamental drawbacks of tubes. On Wednesday, June 29, 1948, at the Bell Labs West Street headquarters in New York City, a press conference was held to announce the invention by Bell Labs scientists of a new amplifying device - it was the transistor. Jack Ward's carefully researched article reminds us that 1998 marks the 50 th anniversary of the first public announcement of the invention of the transistor, which the April 1992 'Physics Today' said, 'caused a revolution in technology and drastically altered society.' The addition of Ron Blackshear's personal recollection of his friendship with John Bardeen, co-inventor of the transistor, gives us further insight into a remarkable 20 th century event. The Transistor's Early History From 1947 to the 1960sBY JACK WARD -Web Edition

Antique Radio Classified: Vintage Transistor Radios