Charles A. Rosencrans (1908-1991) was an RCA engineer who specialized in radio transmission. His notebooks largely consist of fragmentary handwritten notes from both his career at RCA and from his studies in electrical and mechanical engineering at Lehigh University.

The Marconi Wireless Telegraph Corporation of America was founded in 1899 as the American branch of Guglielmo Marconi’s (1874-1937) Wireless Telegraph & Signal Company of London. Because of its emphasis on providing radio transmitter receivers for ships and fostering oceanic communications, the U.S. Navy commandeered the company during World War I. After the war, both government and industry colluded to buy out the British company; they created the Radio Corporation of America in its stead in 1919. This collection includes around 1,300 engineering and technical drawings from the Marconi Wireless Telegraph Company of America . Subjects depicted range from circuit diagrams, wiring layouts, and switchboard schematics to architectural plans for aerial towers and carrying case designs.

The Radio Corporation of America (renamed RCA Corporation in 1969) was best known for its pioneering radio and television development and manufacturing. In addition to consumer electronics, RCA was a major player in the development of electronics for industrial and military applications. The collection contains extensive documentation of RCA’s consumer and industrial products and components. Files include manuals, technical data, advertisements, technical bulletins, catalogs, and training materials.