A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

THE POWER TRANSISTOR

BELL TELEPHONE LABS AND WESTERN ELECTRIC

While Bell Labs and Western Electric manufactured their products mostly for telephone use, they were both involved with large military and government space and defense programs. One of the biggest of these was the Nike surface-to-air missile interceptor program, where Western Electric was the major contractor and the manufacture of the Nike electronic guidance and control systems.  Nowhere was 100% reliability more necessary than in a 24-hour round-the-clock launch system that had to be ready at a moments notice at any time. Product testing and failure predictability became elevated to a whole new level for systems of this type. Thus, it could be seen that the following WE devices may have had their emergence in this new world of quality control and reliability. By 1956, a new Nike 'Hercules' missile program was being developed to replace the earlier Nike 'Ajax' system (all tube), first deployed in 1954. By this time some of the vacuum tubes were being replaced by more reliable solid-state devices, bringing with them lower heat dissipation and lower power consumption.  

In the photo below can be seen two complimentary W. E. Power Transistors. On the left is an F-51619, a Germanium PNP device, first date coded in May of 1956. It is serial numbered '01782' so one would expect production first started in early 1956. The Power Transistor on the right is an F-51618, a similar Germanium NPN device, dated coded in March of 1961. Its serial number is '69937', indicating a sizable number of devices having been made for this particular program needs. Another one of these was made in March of 1957 with a serial number of '4197', indicating production first started again, in early 1956. While many W.E. devices are date coded by week and year, these devices were coded in month and year only, as the specific serial number could be used to trace back to exact production runs and days. The middle picture below shows the small germanium pellet used in higher frequency power transistors. These devices are about 3/4" in diameter, similar to the other W.E. Power Transistors.

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Joe Knight Early Power Transistor History – BTL/WESTERN ELECTRIC  Page 17