Transistor Museum Oral History George Ludwig Explorer I Satellite Transistors Page 12

A Transistor Museum Interview

with Dr. George Ludwig

The First Transistors in Space - Personal Reflections by the Designer of the Cosmic Ray Instrumentation Package for the Explorer I Satellite

Top View of High Voltage GM power supply. Early versions used Raytheon CK79X silicon transistors.

EARLY RAYTHEON TRANSISTORS FOR EXPLORER I

The top scan shows the schematic of the high voltage power supply, required for the Geiger tube to measure radiation levels. [1]. Although known primarily as a leading supplier of germanium transistors, Raytheon was producing a limited number of silicon alloy junction type transistors in the mid 1950s, beginning with the CK79X line, which later became available as the 2N327/8/9 series of transistors. Shown above are the various case styles and colors used on the early Raytheon transistors – note the rapid transition of the CK790 from Black prototype, to Red (limited production) to Red 2N327 (standard). The photo at left (upper) shows the CK790 case style used for Explorer I. Raytheon used a Blue case color to indicate germanium transistors (as with the 2N64 shown above). This device was used, along with the silicon 2N328, in the subcarrier oscillators required for the Explorer signal transmitters. [3] Note, at lower left, the typical Raytheon packaging for these transistors when Explorer was designed.

Go To Ludwig Oral History, Page 13

Raytheon commercial transistor packaging from the 1950s and 1960s.

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