Transistor Museum Early Germanium Power Transistor History by Joe Knight BTL Western Electric Page 8

A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

THE POWER TRANSISTOR

BELL TELEPHONE LABS AND WESTERN ELECTRIC

In order to develop a useful power device for military and government applications BTL began designing the 2N66 PNP Alloy Junction Germanium Power Transistor (the successor to the M1777) by 1954. As was the common practice by then, BTL developed the basic transistor design and manufacturing process then gave it over to Western Electric for implementation and plant production. By early 1955 the RETMA registered 2N66 was in production by W. E., likely at their Laureltown, Pennsylvania plant, where most W.E. Power Transistors were made. The 2N66 was rated at a conservative 1/2 watt dissipated power and was designed for power converter and switching circuits.

The above photo shows a W. E. 2N66 on the upper left made in January of 1955. It uses little stick-on print labels, indicating a likely very early production process. The 2N66 on the upper right, made later in 1955 (26th week), was marked with a regular ink stamping process. The 2N66 used the same hook-eye bottom connecting pins as in the M1777 pictured above. The lower cut-open 2N66 device shows the same alloy junction fabrication design used in the M1777, using the round wire ring 'base' connection on top of the square thin germanium wafer.

Go To BTL/Western Electric Early Power Transistors, Page 9

Joe Knight Early Power Transistor History – BTL/WESTERN ELECTRIC Page 8