Inventing the negative feedback amplifier: Six years of persistent search helped the author conceive the idea “in a flash” aboard the old Lackawanna Ferry

Recently, while watching television at my home in New Jersey, I was pleasantly surprised to see a commercial for a computer-controlled sewing machine. It was the latest of many applications of the negative feedback amplifier that I could never have envisioned when I invented the amplifier more than 50 years ago as a 29-year-old systems engineer at the Western Electric Company's old West Street laboratories in New York City. Although I was certain the amplifier would see broad use inside as well as outside of the Bell System, I did not foresee the tremendous range of applications that would open up for it in almost every type of communication and control system, from radio to automatic pilots, from computers to artificial limbs. The enormous impact of what I had conceived while traveling to work one sunny August morning in 1927 has proved extremely gratifying. I am proud that the amplifier is used today in more than 85 countries and that it has played such an important role in the technological revolution of the past half-century.