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 Gray's led to the myth that Bell had arrived at the Patent Office earlier. Bell was in Boston on February 14 and did not know this happened until later. Gray later abandoned his caveat and did not contest Bell's priority. That opened the door to Bell being granted US patent 174465 for the telephone on March 7, 1876. In 1906 the citizens of the City of Brantford, Ontario, Canada and its surrounding area formed the Bell Memorial Association to commemorate the invention of the telephone by Alexander Graham Bell in July 1874 at his parent's home, Melville House, near Brantford.