Artifact Details


Prototype CK761 germanium transistor

Catalog Number



Physical Object


1954, week 35


Ratheon Semiconductor Division

Identifying Numbers

Model number CK761


overall: 1/4 in x 2 in x 3 1/2 in


The object consists of two transistors, each embeded in plastic. These transistors were used in high speed, computer switching applications.

Per Jack Ward, Transistor Museum -
"Raytheon White Epoxy Pre-production CK761 (2 pieces), germanium PNP alloy junction transistors. By the mid-1950s, as Raytheon had achieved high volume production leadership with hearing aid and low frequency germanium transistor types, improvements in the design of these devices were implemented. An important improvement was the use of manufacturing techniques that would allow operation at higher frequencies and broaden the range of applications to include RF radio circuits and computer switching circuits. Introduced in early 1955, the Raytheon CK760/61/62 transistors were among the first high speed transistors sold commercially. Another major improvement was the introduction of hermetically sealed metal cases, which were intended to prevent the degradation of performance due to moisture penetration through the plastic/epoxy case material used in the early Raytheon transistors. The white epoxy resin case for the units in this lot represent very early pre-production/pilot build devices. Date code: 435 (1954, week 35). Rare - These two units represent a pilot build using the older style epoxy case, with a date code several months prior to the 1955 introduction of the more robust iridescent blue metal case commercial types. These are the only known examples of a pilot build of this very successful product line, likely developed because Raytheon was eager to provide pilot samples to radio and computer companies for engineering studies. "



Collection Title

The Paul Sullivan Collection of Early Semiconductors


Gift of Pat Sullivan Belotti

Lot Number