An Interview with F.W. “Bill” Gutzwiller

 The Early History of the Silicon Controlled Rectifier


Oral History – Bill Gutzwiller (Continued)


As the success of the SCR grew, how did this affect your work and your organization?


The rapidly growing power semiconductor part of Semiconductor Products Department justified the establishment of a separate department, Rectifier Components Department, and I was appointed Manager of Application Engineering for Power Semiconductors, reporting directly to the Manager of Marketing, Bill Hall.  I was given a corner of the office section of the new plant in which to install my application engineering subsection, and I started recruiting engineers and technicians from all over the country and the world to staff my new organization.  I hired Etto VonZastrow, originally from Germany, Denis Grafham from England, Neville Mapham from South Africa, and a few bonafide Americans, John Hey, Dick Rottier, and Jim Galloway, as well as several technicians for our laboratory.  By this time we were into the third edition of the SCR Manual, and my new recruits helped me grow the manual and its contents into something rivaling the New Testament in size.  Every day it seemed, I and my people were discovering something new in power semiconductors, what they could do, and the circuits in which they could be used.  During these busy years, I received over 20 U.S. patents for my ideas.


Please describe the circumstances that led to the development of the Triac.





Oral History – Bill Gutzwiller (Continued)


The SCR, which I had been instrumental in bringing to life, was able to control only one half of an alternating current cycle, rather than both the positive and negative half cycles.  To get a full-cycle lamp dimmer and full control of the A-C power line required two SCR’s and considerable control circuitry.  This setup was now being used in lamp dimmers and other power control applications throughout the world.  For months I grappled with the idea of doing the whole job with just one power semiconductor device and much simplified control circuitry.  I laid out the challenge to our advanced engineering people, who were at this time led by my colleague and old canoeing friend from Lyons, Finis Gentry.  He kept me supplied with all of the newly evolving semiconductor concepts and mechanisms being developed by his people and GE’s Electronics Laboratory in Syracuse and Research Labs in Schenectady, suggesting that remote or junction gate structures might help address the challenge.


One late night, a combination of several of the new developments occurred to me as a possible answer: technically speaking, a five-layer NPNPN power semiconductor with shorted emitters and a remote gate.  I brought my speculative sketch in to Finis the next day and explained it.  He said, “You know, it just might work!” 


Go To Gutzwiller Oral History, Page 11




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