Norman B. Krim

Transistor Museum Historic Profile

Recognizing Significant Contributions to 20th Century Semiconductor History and Technology

Notable Contributions, Continued


Above is a photo from a 1954 in-house Raytheon publication, showing Norm Krim (left) being congratulated by the governor of Massachusetts for the great success of Raytheon transistors.


By mid-1954, Raytheon was producing large numbers of germanium alloy junction transistors, primarily for the hearing aid market.  The CK718 shown above was the high performance twin of the CK722.

Above is the cover of one of the most widely read of the 1950s transistor hobbyist books.  This was published by Raytheon to generate interest in the CK722.

As shown above, the CK722 was produced in three case styles, starting with the black epoxy case in 1953, followed by the blue metal case in the mid to late 1950s, and ending with the silver metal case in the 1960s.  The CK722 was first introduced by Norm Krim at Raytheon to support the hobbyist market with devices that didn’t meet the stringent requirements of the CK718 hearing aid transistor.   In the 1940s/50s, Raytheon was a leading manufacturer of subminiature vacuum tubes (shown above) for hearing aids.  At right is a list of Norm’s vacuum tube patents.  

N. B. Krim



Filed Aug. 17, 1940


N. B. Krim Patents: 2274554, 2355083, 2424990, 2433373, 2452061, 2464241

Norman B. Krim – Additional Historic Material

Use these links to review additional historic material about Norm Krim and the CK722.

IEEE Spectrum Article          CK722 Museum Webpage          Transistor Museum Krim Audio Clips

COPYRIGHT © 2009 by Jack Ward.  All Rights Reserved.