EARLY TRANSISTOR HISTORY AT RCA

Fred L. Hunter

 

Oral History – Fred Hunter

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Here are various views of the 2N331 gemanium alloy transistor which was developed by Mr. Fred Hunter in the late 1950s at the RCA Semiconductor facility in Somerville NJ.  The TA-1650A unit shown in the top photo represents the “pre-production” or developmental type which was the precursor of the 2N331.  RCA used the “TA” (Transistor Amplifier) numbering system for developmental types. According to documentation provided by Mr. Hunter, here are some mechanical features for the 2N331: PNP, Germanium, Antimony Impurity for N-region, Indium Impurity for the Collector, Indium-Silver-Gallium Impurity for the Emitter, Case filled with DC4 Silicone grease,  Leads are sealed with glass, Lead material is Dumet (Copper Clad Steel), and the case is gold plated on nickel-iron, copper coated.  The germanium pellet is 84 x 84 x 5.5 mils,  Case outline is TO-9.  The 2N331 is intended primarily for industrial audio applications.

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Oral History – Fred Hunter

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Here is a copy of a page from a lab report developed by Fred Hunter as part of his early work on point contact transistors at RCA.  Note the date (8/17/51 and the initals (FLH) on the lower right of the page.  This graph shows the performance curves of a single point contact transistor, as observed on an oscilloscope, after the transistor has been “formed” – the forming process involved pulsing the collector/base junction of the N-Type transistor with a capacitor charged to a voltage between 130 to 150 vdc.  The forming process was quite labor intensive, but also essential, since the performance of a point  contact transistor improved dramatically after forming.    It is interesting to note the dramatic progress shown between the almost “hand made “ aspects of transistor development illustrated in this lab report, compared to the high volume,  mass production, nature of transistor development shown by the 2N331.  This was only a span of 5 years, from 1951 to 1956, but represents tremendous progress.

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