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Poulsen, Valdemar

(Encyclopedia)Poulsen, Valdemar välˈdəmär poulˈsən [key], 1869–1942, Danish electrical engineer. He invented (1898) the telegraphone (an early wire recorder) and the high-frequency Poulsen arc used in wirel...

Jansky, Karl Guthe

(Encyclopedia)Jansky, Karl Guthe, 1905–50, American radio engineer; b. Norman, Okla. After graduating (1927) from the Univ. of Wisconson, he joined the Bell Telephone Laboratories. While trying to determine the c...

piezoelectric effect

(Encyclopedia)piezoelectric effect pīēˌzōĭlĕkˈtrĭk [key], voltage produced between surfaces of a solid dielectric (nonconducting substance) when a mechanical stress is applied to it. A small current may be ...

photoelectric effect

(Encyclopedia)photoelectric effect, emission of electrons by substances, especially metals, when light falls on their surfaces. The effect was discovered by H. R. Hertz in 1887. The failure of the classical theory ...

Giaever, Ivar

(Encyclopedia)Giaever, Ivar, 1929–, Norwegian-American physicist, Ph.D. Rensselaer Polytechnic Institute, 1964. He was a researcher at General Electric from 1954 to 1988, when he joined the faculty at his alma ma...

Broglie, Louis Victor, duc de

(Encyclopedia)Broglie, Louis Victor, duc de, 1892–1987, French physicist. In 1928 he became professor in the faculty of sciences, Univ. of Paris. It was known from the earlier quantum theory that light waves some...

Richardson, Lewis Fry

(Encyclopedia)Richardson, Lewis Fry, 1881–1953, British physicist and pioneering meteorologist, grad. Cambridge (1903), Univ. of London (B.Sc. 1929). Richardson worked at the National Physical Laboratory (1902–...

Baze, Russell Avery

(Encyclopedia)Baze, Russell Avery, 1958–, Canadian-American jockey, b. Vancouver, Canada. He rode primarily at tracks in N California. In 2006 he surpassed Laffit Pincay, Jr.'s record for career wins, and in 2008...

radio

(Encyclopedia)CE5 A. AM transmitter B. AM receiver radio, transmission or reception of electromagnetic radiation in the radio frequency range. The term is commonly applied also to the equipment used, especially...

radar

(Encyclopedia)radar, system or technique for detecting the position, movement, and nature of a remote object by means of radio waves reflected from its surface. Although most radar units use microwave frequencies, ...