Transistor Museum Early Germanium Power Transistor History by Joe Knight Amperex Page 2

A SURVEY OF EARLY POWER TRANSISTORS

by Joe A. Knight

AMPEREX 1950s GERMANIUM POWER TRANSISTORS

I have never seen an Amperex 2N115. Again, this item was not very competitive by 1956 when all the other manufacturers had come out with higher power TO-3 types and may explain it's apparently low sales. In addition, the materials and construction costs of this very involved item had to have made it a very expensive power transistor to make and sell at the time. As can be seen in the cut-out sample, this had three layers of steel housing, three glass relief insulators, a large insulated bottom layer, and the top-hat heat sink, which is made with some kind of hard resin inside with a copper heat tab. Not really sure how effective this all was to it's over-all dissipation rating. No matter, it was not inexpensive. Amperex did not really get into the power transistor market in the U.S. after this, at least in the 50's. Mullard/Valvo did move forward with their own TO-3 power types later.

~~______________~~

Joe A. Knight Early Power Transistor History – AMPEREX Page 2