Transistor Museum Early Germanium Power Transistor History by Joe Knight BTL Western Electric Page 20

A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

THE POWER TRANSISTOR

BELL TELEPHONE LABS AND WESTERN ELECTRIC

By 1957, Bell Labs needed to update some of their earlier 'in-house' power transistors, such as the W.E. 6A and 6B Power Transistors, to reflect the new power potential of their other semiconductor products. Thus, by mid-1958, the WE 9A was released as a replacement for the 1955 WE 6A type. It too was developed from the earlier Model 2074 Power Transistor. The WE 9A was a PNP Alloy Junction Germanium transistor housed in an all-copper case with the same TO-32 base threaded stud design, and almost identical to the 2N463 type, made for government and military usage.

The earlier version WE 9A's had the metal-grey finish as seen on the left hand device above. By the early 1960's Western Electric has standardized on the gold-plated finish for all their semiconductor devices, as seen in the middle 1963 device above. All these first WE 9A types had the regular exhaust tube still pinched off on the top. By the mid-1960's, WE had eliminated the top exhaust tip as seen on the far right device above from 1966. The cut-open WE 9A seen above reflects this new element design which allowed for its higher 30-watt dissipation rating.

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