An Interview with F.W. “Bill” Gutzwiller

 The Early History of the Silicon Controlled Rectifier


Oral History – Bill Gutzwiller (Continued)


Partial List of Representative Patents Awarded to F. W. Gutzwiller.


[1] Patent 3,040,270 Granted 6/16/62.

“Silicon Controlled Rectifier Circuit including a Variable Frequency Oscillator”


[2] Patent 3,222,583 Granted 12/07/65.

“Control Systems”.

This circuit has been used and continues to be used for controlling the speed of universal motors in millions of appliances, hand tools, and sewing machines throughout the world.


[3] Patent 3,275,909 Granted 9/27/66.

“Semiconductor Switch”.

This is the basic patent for the TRIAC AC switch used worldwide in almost every lamp dimmer, static AC switch, and electric heating control.


[4] Patent 3,404,327 Granted 10/01/68.

“Conversion Systems Comprising SCRs with Gate Control Arrangements”.

This circuit patent is basic to at least a half of all SCRs used in the world.  It covers the use of SCRs in phase control circuits, the basis of industrial motor drives of all horsepower ratings, battery chargers, and lighting systems.


[5] Patent 3,535,615 Granted  10/20/70.

“Power Control Circuits including a Bidirectional Current Conducting Semiconductor”.

The patent covers basic circuits using the TRIAC switch.  All lamp dimmers and static AC relays are covered by this patent.



For additional material on patents [2] and [3] above, use this link:


Go To Gutzwiller Oral History, Page 13



Oral History – Bill Gutzwiller

These Audio Links are Excerpts

from a 2005 Interview with

Bill Gutzwiller.


Working with the First Germanium Power Rectifiers in 1955 

Bill Gutzwiller Audio Clip #1



Developing the First

SCR Circuit in 1957

Bill Gutzwiller Audio Clip #2



The First Commercial SCR Applications

Bill Gutzwiller Audio Clip #3



Comments on Rapid Growth of the SCR

Bill Gutzwiller Audio Clip #4



Developing the GE SCR Manual

Bill Gutzwiller Audio Clip #5



How the Triac was Developed

Bill Gutzwiller Audio Clip #6



Comments on High Level of Teamwork Leading to SCR and Triac Success

Bill Gutzwiller Audio Clip #7




COPYRIGHT © 2005 by Jack Ward.  All Rights Reserved.  http://www.transistormuseum.com/