1930s-1940s By van32202 Period: Jan 12, 1930 to Jan 12, 1950 1930s-1950s Apr 16, 1931 Vannevar Bush creates the differential analyzer Apr 15, 1935 First Telephone Call Around the World Jan 1, 1937 The Idea of the Electronic Computer is Born Jan 19, 1937 Transistor Invented Jan 1, 1938 "A Symbolic Analysis of Relay and Switching Currents" published Sep 1, 1939 World War II Begins Jan 1, 1948 "A Mathematical Theory of Communication" published Jan 18, 1949 "Communication Theory of Secrecy Systems" published