Transistor Museum Early Germanium Power Transistor History by Joe Knight BTL Western Electric Page 3

A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

THE POWER TRANSISTOR

BELL TELEPHONE LABS AND WESTERN ELECTRIC

The above photo shows a single Type A with added cooling fins on the left and a "push-pull" design pair on the right.

Thus begin the development by BTL of a long line of Power Transistor devices, manufactured mostly by Western Electric. As Bell Labs resided in Murray Hill, New Jersey, they assigned a "M" prefix to all their prototype projects as that would identify those devices as originating from there. These early MXXXX transistors were designed and built in-house by BTL while some would later be programmed for manufactured assembly by Western Electric.

Some of the first small-signal transistors were originally made at Murray Hill, such as the BTL M1689 and M1698 PTC types. On the first of October, 1951, the first true transistor manufacturing plant was started up at the Western Electric facility in Allentown, Pennsylvania. Thus, these new PTC devices were given the "A" prefix to denote their new origin and the first ones made were called the W.E. A1689 plastic bead type and the A1723 cartridge type transistor, both point contact.

Go To BTL/Western Electric Early Power Transistors, Page 4

Joe Knight Early Power Transistor History – BTL/WESTERN ELECTRIC Page 3