TitleCK742 Germanium diode
Date1954 week 28
ManufacturerRatheon Semiconductor Division
Dimensionsoverall: 2 in x 1/4 in x 1/4 in
DescriptionThe date code is 428 (1954, week 28).
Per Jack Ward, Transistor Museum -
"Germanium gold bonded contact diodes. Mid- 1950s. Raytheon was a major manufacturer of germanium diodes, starting it the early 1950s. Mastering this technology allowed Raytheon to quickly move into mass production of germanium junction transistors, as the manufacturing processes were similar. Many of these 1950s Raytheon devices used the proprietary “CK” numbering system. The devices in this lot were sold as computer switching diodes, and use the unique black epoxy case characteristic of Raytheon early 1950s semiconductors. By 1955, Raytheon relabeled this diode type with the industry standard “1N307” equivalent id and a more robust metal case style. Date code: 420 (1954, week 20). Rare to Common - early black epoxy case style and proprietary “CK” numbering approach for Raytheon diodes was used for a short time only, with low volume production."