An Interview with Paul Penfield Jr.

Oral History – (Continued)



The February 1956 issue of Radio and Television News magazine featured an article by Paul on the topic of the newly emerging germanium power transistor technology.  Although many of Paul’s transistor articles were devoted to construction projects, he also authored a number of articles which provided an overview of transistor technology to the hobbyist and service technician audience.  This power transistor article is an example of the latter category.  The top scan is a section of the front page of the article, showing a research physicist watching over an electric induction furnace used to grow germanium crystals at Minneapolis-Honeywell. This company was one of the early leaders in power transistor technology.  The photo to the top right is also from this article and illustrates various power transistors available in 1956 – from top to bottom these are: Transistron 2N83A, Amperex 2N115, Texas Instruments 953, Transistor Products X-107, Sylvania 2N95 and Minneapolis-Honeywell 2N57.  The photo on the lower right is a recent image of several transistors donated by Paul to the TransistorMuseum.  Note that the 2N95 and the 2N57 are identical to the two transistors shown in the magazine image, separated by almost 50 years.  These are truly historic devices!  The Raytheon CK727 transistor shown below the 2N57 is an example of a low noise audio transistor of the type used by Paul in several of his construction articles.  This unit was also donated by Paul and provides a basis for size comparison with the power transistors.  









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