Transistors.

Ernest Braun and Stuart Macdonald,Revolution in Minature(1982):
The 'major invention of the century' occurred at the Bell Laboratories in Murray Hill, New Jersey on 23 December 1947. The transistor, a device which used semiconductor material to amplify or switch an electric signal, was discovered on that day. . .The germanium point contact transistor was in commercial production at Western Electric by 1951 and also in experimental production in some other large companies, such as Raytheon, at this time. . .By April 1952, the junction transistor was in production at Western Electric, though at less than one hundred a month. Sample lots were also available from Raytheon, RCA and General Electric. . .In May of 1954, Texas Instruments announced it had succeeded in making a silicon transistor. . .The silicon transistor, with its capacity to work in much higher temperatures than any germanium transistor, was of much greater interest to the Military. This was to become a highly significant factor,(pp.33,54,55).