"General Radio was founded in Cambridge in 1915 by Melville Eastham and four other investors to manufacture radio measuring instruments and parts. Initially, the company focused on transmitting and receiving components and precision measuring instruments, as well as a few complete receiving sets. ... By 1924, General Radio began its decades of dominance of the high-end instrument market. During the time, the company introduced a host of unique instruments, including the first commercially available oscilloscope. Two products developed in the 1930s found major uses during World War II: the Variac variable autotransformer and the Strobotac, the first commercial strobe light. "