Transistor Museum Early Germanium Power Transistor History by Joe Knight BTL Western Electric Page 21

A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

THE POWER TRANSISTOR

BELL TELEPHONE LABS AND WESTERN ELECTRIC

By mid-1959, Bell Labs had released the WE 9B as a replacement for 1956 WE 6B type. While identical looking to the WE 9A, it was rated as a PNP Germanium medium-power device with only 2.8 watts of dissipated power. The WE 9B was designed primarily for switching circuits and as a core-memory driver, with a cut-off frequency of 25kHz. It too was a PNP Alloy Junction Germanium Power Transistor as seen in the left device below.

About this same time in 1959 Bell Labs released a new power device called the WE 9D, as seen above on the top right, also a PNP Alloy Junction Germanium transistor. While its power was similar to the WE 9B with only 2.8 rated watts of dissipation, it was designed to be operated out to 3MHz, again as a core driver and a transmission device. The cut-open device above reflects the interior construction of both the WE 9B and 9D Power Transistors. Both these power transistors were again based upon the new TO-32 design.

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