Artifact Details


Transistor prototypes

Catalog Number



Physical Object


Early to med-1950s


Ratheon Semiconductor Division (?)

Identifying Numbers

Other number 113 On one of the pieces.
Other number 124 On one of the pieces.
Other number 127 On one of the pieces.
Other number 43 On one of the pieces.


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


The object consists of four pieces

Per Jack Ward, Transistor Museum -
"Raytheon Clear Epoxy CK718 Prototypes (4 pieces), experimental germanium PNP alloy junction transistors. Early to mid-1950s. Raytheon was the first to market readily available germanium alloy transistors, with the CK718/721/722 devices, beginning in late 1952. Commercial versions of these transistors used black epoxy resin cases, with the type id and date codes stamped on the case. Raytheon used white resin devices for experimental studies and prototypes. Often these prototypes were hand labeled or otherwise identified with tags. The transistors in this lot are unique in that the case material is a translucent epoxy/plastic which allows visual inspection of the internal elements of the transistors. In addition, embedded inside the case are id tags with formal printed number identification for each transistor; these devices were likely used in an engineering study. The engineering studies may have focused on case material suitability for protecting the transistor junctions from degradation due to moisture penetration through the plastic case, which was a known problem with early transistor types. Note that the case shape and size of the transistors in this lot are the same shape and size as the standard Raytheon CK718 type, and the red paint dots used to mark the “collector” connection are a similar technique used for the CK718. Rare – the translucent plastic case material used for these Raytheon transistors is very unique, since all other known examples of 1950s Raytheon plastic experimental transistors use either white or black resin. Likely only a very few of these Raytheon experimental transistor types were developed."




Collection Title

The Paul Sullivan Collection of Early Semiconductors


Gift of Pat Sullivan Belotti

Lot Number