Alcatel-Lucent 1947, John Bardeen, Walter Brattain, William Shockley of Bell Labs invented the transistor. In 1956, they received a Nobel Prize for their invention. The transistor led to an electronics revolution during the post-war boom. The transition from vacuum tubes to transistors enabled all technologies to be built on a smaller scale and use less electricity. Items that before required large dedicated spaces, could now fit into a home or even on a kitchen counter. In 1954, Gerald Pearson, Darryl Chapin and Calvin Fuller invented the solar cell. Telstar, the first active communications satellite also developed by Bell Labs and launched
Invention of the telephone receiver. Gray did not convert his caveat into a patent application until after the caveat had expired and hence left the field open to Bell. When Gray applied for a patent for the variable resistance telephone transmitter, the Patent Office determined "while Gray was undoubtedly the first to conceive of and disclose the (variable resistance) invention, as in his caveat of 14 February 1876, his failure to take any action amounting to completion until others had demonstrated the utility of the invention deprives him of the right to have it considered." The carbon microphone was independently developed around 1878 by