Transistor Museum Early Germanium Power Transistor History by Joe Knight BTL Western Electric Page 27

A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

THE POWER TRANSISTOR

BELL TELEPHONE LABS AND WESTERN ELECTRIC

Next on the scene in 1962 from Bell Labs was the WE 2N1675, a NPN Silicon Diffused Mesa high-power device rated at over 50+ watts of dissipated power. As seen in the two left samples below, it uses the same TO-32 enclosure design as the older Germanium 2N463 Power Transistor, rated at just 35 watts. However, the increased power potential of Silicon over Germanium is revealing itself wherein the 2N1675 now has over 50% more power capacity for the same size device.

The cut-open sample above reflects the inter-digitized wafer assembly typical of most high-power devices then being made (as seen also in the newer Westinghouse and Pacific Semiconductor Power Transistors). The middle sample above shows the flush top design, from about 1963. The far right sample is a military/government type called the Silicon Diffused GA-53913 from the mid-60's, likely the twin to the 2N1675.

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Joe Knight Early Power Transistor History – BTL/WESTERN ELECTRIC Page 27