History of the transistor about 15 volts". Brattain and H. R. Moore made a demonstration to several of their colleagues and managers at Bell Labs on the afternoon of 23 December 1947, often given as the birth date of the transistor. The "PNP point-contact germanium transistor" operated as a speech amplifier with a power gain of 18 in that trial. In 1956 John Bardeen, Walter Houser Brattain, and William Bradford Shockley were honored with the Nobel Prize in Physics "for their researches on semiconductors and their discovery of the transistor effect". Twelve people are mentioned as directly involved in the invention of the transistor
Invention of the telephone Company, and the results were covered up by STC's chairman Sir Frank Gill to maintain Bell's reputation. An early voice communicating device was invented around 1854 by Antonio Meucci, who called it a "telettrofono". In 1871 Meucci filed a caveat at the US Patent Office. His caveat describes his invention, but does not mention a diaphragm, electromagnet, conversion of sound into electrical waves, conversion of electrical waves into sound, or other essential features of an electromagnetic telephone. The first American demonstration of Meucci's invention took place in Staten Island, New York in 1854. In 1861, a description of it was