Transistor Museum Early Germanium Power Transistor History by Joe Knight Transistor Products Inc Page 2

A SURVEY OF EARLY POWER TRANSISTORS

by Joe A. Knight

TRANSISTOR PRODUCTS INC 1950s

GERMANIUM POWER TRANSISTORS

More Transistor Products germanium power types. These are their massive devices with the extruded aluminum heat-sinks. BTW, these TP/Clevite photos deal only with the pre- "TO-3" types. That series will be covered in another photo layout since these became a whole different development series for CT/P.

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

The first item is a CT/P production device, an X122 (rated at 7.5 watts dissipation/2.8 watts output), from early/mid 1955. The actual transistor enclosure itself for this one and the last item, looks like a type X125 (Page 1) that has been inserted into an opening of the heat-sink in order to give it the larger dissipation rating. The next one appears to be a developmental version of the last device. However, its transistor enclosure is bolted into the very large radial fin heat-sink with a threaded bolt on its bottom. The lower opened device, similar to the one above it, shows the early type of power device construction that Prof. Fletcher helped develop while at Transistor Products. The last item is a CT/P production device called an X120 (rated at 15 watts diss./5.3 watts output) from early/mid 1955. This thing is about as big as your fist. Not sure where anyone would use this huge device as any modern tube, smaller in size, would be more practical. And of course the whole TO-3 series of transistors came out the following year and put these things in the junk pile very quickly. Probably why so few exist.

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