This file consists of Edison's brief before the Board of Examiners-in-Chief in the case of Zipernowsky v. Edison, which involved conflicting claims over alternating current systems. Karl (or Charles) Zipernowsky (1853-1942) was a Hungarian electrical engineer. Along with Otto Blathy and Maximilian Deri, he invented the ZBD alternating current transformer to convert high-voltage electric current to lower-voltage current. Zipernowsky and his partners received several patents on their inventions. This interference involved an application filed by Edison on November 19, 1886, and an application filed by Zipernowsky on March 19, 1888. In this brief Edison's attorneys dismissed Zipernowsky's "alleged invention" as being "nothing more than the rearrangement and reversal of well-known devices." The Board, however, ruled in favor of the plaintiff. Courtesy of the National Archives.