Transistor Museum Early Germanium Power Transistor History by Joe Knight Transistor Products Inc Page 3

A SURVEY OF EARLY POWER TRANSISTORS

by Joe A. Knight

TRANSISTOR PRODUCTS INC 1950s

GERMANIUM POWER TRANSISTORS

Last one of this Transistor Products/Clevite series. These are all medium to large types but not actual production versions.

L-to-R: A small paper-clip is shown for scale.

The first is a medium power device from the c. 1954/55 era as it has a CT/P decal on it. Other than the number '4' printed on it nothing else is known (= '4' watts ??). The next item is a TP device c.1954, about an 1 3/8" in diameter. Both these devices have a threaded bolt on the bottom to allow attachment to some larger heat-sink. Such a device is shown next, about an inch in diameter, bolted into an extruded copper heat-sink. Finally, what no doubt has to be the world's first water-cooled power transistor, from CT/P, c. 1955. The upper device body, about 1 1/4" in diameter and 1" tall, is threaded into a round copper body bottom where the water can circulate between the input and discharge tubes. Prof. Fletcher says they were experimenting with devices up to 100 watts by the time he left in 1955 so this may very well have been the way they were able to extract so much heat, by water-cooling. The leads are very heavy wire which would allow for a large amount of current.

~~______________~~

Joe A. Knight Early Power Transistor History – TRANSISTOR PRODUCTS INC Page 3