In 1934, Haeff left Caltech to work for RCA's research and development team, where he invented the inductive output tube in 1939 . With the United States'entry into the Second World War in 1941, Haeff joined the United States Naval Research Laboratory as a consulting physicist, helping with the development of radar and inventing a pulse jammer.
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On June 10, 2014, Kevin Hayes was issued U . S . Patent 8, 749, 310 for " amplifier bias control . " This patent covers the only known technique for observing the true underlying quiescent current ( idle current ) of an output tube ( or transistor ) under dynamic signal conditions, and then holding it to the stable target value with a precision of 99 % or better.
