Otto A. Knopp
Otto Albrecht Knopp (24 August 1877 – 19 December 1946) was a German-American innovator of the standard testing transformer and the Compensation Winding. He was also the patentee of what has become known as the Knopp set in honor of him,[1] and the author of a number of technical reports, including New Current Balance for Calibration Work, published in 1920.[2]