Artifact Details


CK722 Germanium transistor

Catalog Number



Physical Object


The object was very low quality performance, and was sold to hobbyists.

Per Jack Ward, Transistor Museum -
"Raytheon CK722 (1 piece), germanium PNP alloy junction transistor. The Raytheon CK722 is one of the best known and well-remembered transistors from the 1950s/1960s. This device was introduced by Raytheon in early 1953 through a series of ads in magazines designed for the electronics hobbyist, such as Radio Television News and Radio Electronics. Throughout the 1950s and into the 1960s, hundreds of CK722-powered construction project articles appeared in similar magazines. Many of the electronics and computer professionals of the past five decades remember the CK722 as their first transistor. The first units had cases of black epoxy, while later units were made with blue or silver metal cases. These latter two case types actually consisted of a smaller hearing aid transistor encapsulated inside the metal case. The Raytheon CK718 was the first mass produced germanium alloy junction transistor, and was manufactured in large quantities for use in hearing aids – yields from these early transistor manufacturing lines were quite poor, so Raytheon developed a successful marketing strategy to “repurpose” those CK718s which weren’t quite good enough for the demanding hearing aid market (not enough gain or too noisy) - these production fallouts were labeled as CK722 and sold as affordable and readily available hobbyist transistors. Date code: 313 (1953, week 13). Common - with tens of thousands sold to hobbyists and experimenters, first as black epoxy units as shown, and later replaced by iridescent blue case units, beginning in mid-1950s, and later silver case units in the early 1960s."

Date code: 313 (1953 week 13)




Ratheon Semiconductor Division

Place Manufactured


Identifying Numbers

Model number CK722


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



Collection Title

The Paul Sullivan Collection of Early Semiconductors


Gift of Pat Sullivan Belotti

Lot Number