Transistor Museum Early Germanium Power Transistor History by Joe Knight BTL Western Electric Page 15

A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

THE POWER TRANSISTOR

BELL TELEPHONE LABS AND WESTERN ELECTRIC

In 1955 Motorola had standardized the first Power Transistor basing design, called the RETMA "TO-3" base. In 1956 various transistor manufacturers released their first RETMA registered TO-3 based devices, including CBS (2N155), Motorola (2N176), Bendix (2N234), Sylvania (2N242), T. I. (2N250), and CTP (2N257). By 1956, Bell Labs was developing another standard base power device of their own called the WE GF-40010. It was a PNP Alloy Junction Germanium Power Transistor, rated at 1/2 watt. This was released c. 1956 and is shown below.

As can be seen above on the right, its internal element construction is similar to the WE 6A power transistor released late in 1955, which has the same ratings. The top exhaust tip was still being used. These were copper top and bottom housings, cold welded together (a process WE developed and licensed to others).

The next image below shows the RETMA "TO-32" basing design which WE was to use for the next several years for all their higher power output devices.

As seen above on the right, while using the same threaded stud connection as on the WE 6A, the WE GF-40010 stud itself is cut away in order to facilitate correct insertion orientation. About this same time Western Electric began applying a light gold plating on all the connecting bases and pins of all their semiconductors. This in order to minimize corrosion and maximize electrical conductivity and soldering.

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