by Joe A. Knight



ABOVE, L-to-R: The first item is an early developmental transistor, hand labeled "QC113", and similar to the infamous CK718-725 series that Raytheon came out with in 1952-1953, but without any color, just the white resin (most all the Raytheon developmental devices had a QC prefix). Additionally, this has a copper heat sink attached to the element structure to give it some additional heat dissipation, maybe up to 1/4 of a watt. This device likely dates from 1953/54 and is a likely predecessor to the one shown in the Transistor Museum's Photo Gallery on Raytheon Blues and identified as the "CK750-1", their first low power transistor from late 1955. These were likely only made as small sample lots. The second item is a TO-3 type transistor labeled "DEV16" . This is a NPN Silicon output device as is the cut-open device next to it - both still work. We know Raytheon was working with silicon devices at least by 1956 as by early 1957 they released their first Silicon small-signal "RED" series called the CK790, CK791 and CK793 - designed mostly for higher temperature military service (see Transistor Museum Photo Gallery). The fact that these above two TO-3 devices have that 1956/57 style case leads one to believe these are from that 1957 time period. However, it does not appear Raytheon ever made a silicon TO-3 production item. (The first silicon TO-3 output devices, the 2N418-422 series, were made by Bendix in mid-1957. These came out just after T.I. introduced the first high-power silicon types, the large square-based 2N389/2N424 series, earlier in 1957). The last item, the QC155 (not working), may coincidentally have the "155" number as a reference to Raytheon second-sourcing some of the CBS output transistors in the late 50s/early 60s. While the 2N155 (see Power Transistor CBS page) was the first Germanium TO-3 device made by CBS, we know from the Sams transistor substitution handbooks that Raytheon did later second source the CBS 2N155, 2N156, 2N158 and 2N158A output devices. So this QC155 device may have been an early pre-production version of that effort just to prove their manufacturing capability. This device may also have lead to the in-house Raytheon TO-3 Blue germanium type, called the CK 753 (see Transistor Museum Photo Gallery on Raytheon Blues), released in 1957 and likely only available in small sample lots.







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Joe A. Knight Early Power Transistor History RAYTHEON Page 2