The Transistor at 75, and the Raytheon CK722 (Pete's First Transistor)

 

https://www.eejournal.com/article/the-transistor-at-75-the-first-makers-part-1/

Part 4 is especially interesting to us because of the N6QW-CK722 connection: 

     Raytheon: Raytheon started making vacuum tubes in 1922. During World War II, the company made magnetron tubes and radar systems. Raytheon started making germanium-based semiconductor diodes in the 1940s and, just months after BTL announced the development of the transistor in late 1947, started making its own point-contact transistors using germanium salvaged from Sylvania diodes. After attending the 1952 BTL transistor symposium and licensing the alloy junction transistor patents from GE, the company quickly started making germanium transistors including one of the most famous transistors of that generation, the CK722, which was simply a rejected commercial CK718 transistor with downgraded specs for the hobby market. (Jack Ward has created an entire museum around the Raytheon CK722 PNP transistor.) Raytheon exited the semiconductor business in 1962.

Here are all of our blog posts on the CK722: 

https://soldersmoke.blogspot.com/search?q=CK722

Here is our post on Pete Juliano's CK722: 

https://soldersmoke.blogspot.com/2015/03/pete-juliano-homebrwing-with.html