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A SURVEY OF EARLY POWER TRANSISTORS by Joe A. Knight PHILCO 1950s GERMANIUM POWER TRANSISTORS
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The Philco Corp. was another of those mega-electronic and appliance manufacturers. Having started out as the "Philadelphia Storage Battery Co." in 1906 and then as "Philco" in the 20's, they went on to become a major Radio and TV supplier to dealers all over the world. In 1947 Philco bought the National Union (NU) Cathode-Ray tube manufacturing plant in Lansdale, PA and began making their own radio and TV tubes, having bought Sylvania and Hytron tubes previously for all their electronic products. This plant came to be known as the "Lansdale Tube Co., Division of Philco Corp." and produced tubes and transistors for many years. In early 1956 Philco expanded their transistor production by building a new plant in Spring City, PA. Philco's own Research and Development Labs were located in Philadelphia. Philco started out in the semiconductor business in 1951 and like most companies new to this field of technology attended the Bell Labs Symposium in April 1952 and bought the license agreement from Western Electric to use their patent technology. Philco was also a major player in automobile radio manufacturing from the earliest days and was no doubt very interested in useful Power Transistors for car-radios. Their earliest semiconductor success came in the field of small-signal devices with the advent of the Surface-Barrier design in 1953 which provided the first high frequency types useful in VHF circuits. |
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Late in 1955, Philco brought out a portable battery-powered transistorized phonograph player, using what is likely the world's first commercial 'solid state' amplifier (w/crystal cartridge input, using two small L5022 output devices, push-pull, to the speaker), called the "TPA-1". Shown at left is a section of the front cover of the October 1955 Philco Service Supervisor – note the interesting comments on the industry’s first transistorized phonograph. This is about one year after the introduction of the Regency TR1 radio, which was the industry’s first all transistor radio – this timely introduction of the TPA-1/2 phonograph is a clear indication that Philco was committed to the new transistor technology. It is likely Philco had begun their own Power Transistor research by 1955 and this soon brought about the release of their own unique 'half-dome' (or flying saucer) output devices by the end of 1956, especially for use in the new transistor car-radios. |
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COPYRIGHT © 2007 by Jack Ward. All Rights Reserved. http://www.transistormuseum.com/ Joe A. Knight Early Power Transistor History – PHILCO |
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