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

A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

CLEVITE TRANSISTOR PRODUCTS 1950s/60s GERMANIUM POWER TRANSISTORS

L-TO-R: The first two are cut open samples of the two devices shown on the previous page in the bottom photo, lower left. The middle item, a U.S. Army 2N297, is an example of the sizable influence that the Armed Services had on the early design and development of the transistor industry. Most of the early transistor research costs were paid for by Defense Department contracts to further the development of semiconductor devices for possible military applications. And as such they had the ability to specify specific devices marked for their inventory and use. The ARMY Signal Corps was probably the biggest consumer of all the branches and are the most commonly found devices today. In the early years the military had top priority in the allocation of available production quantities and the commercial interests had to work with what was left over. Which probably explains why most of the larger electronic manufacturers were keen to get into the transistor business. They certainly did not want to be held hostage by some competitor for their own internal consumption of semiconductor devices. The last two far right devices, the AR-12 and SP147 are examples of likely special order items made by CTP. All CTP TO-3 devices had the raised ends on the base which curved around the top cover (see 2N257, middle row). Different manufacturers used different base end designs to distinguish their product lines from the others.

By early 1957, Clevite had released more power devices, the CTP-1104, CTP-1108, CTP-1109, and CTP-1111 - all rated at 25 watts. These however were all TO-3 types as I suspect the top-hat series was dropped once the first 2N257 type was released in mid-1956.

~~______________~~

Joe Knight Early Power Transistor History – CLEVITE TRANSISTOR PRODUCTS Page 2