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Historical
Background
Soon after the invention of point
contact transistor technology at Bell Labs in 1947, William Shockley
developed the theoretical basis for the junction transistor. By 1952,
Western Electric had implemented early production junction devices and
registered the 2N27, 2N28 and 2N29 type numbers with the current industry
standards association (RTMA, later to be known as JETEC/JEDEC). The 2N27
and 2N28 were in large scale production by 1955, followed by the 2N29 in
1957. These historic types are excellent examples of the first junction
transistor technology (known as grown junction), and represent the “state
of the art” for mid- 1950s semiconductors.
The WECO types 2N27, 2N28 and 2N29 were the first junction
transistor types registered with the industry standard “2N” RTMA numbering
system. The earlier 2N21 thru 2N26 types were also registered by Western
Electric, but were point contact devices. Indicative of the rigorous
manufacturing and quality standards implemented by WECO, your 2N27 and 2N29
units, although 50 years old, are still functional. These are truly
historic transistors!
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