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1962 Nick Holonyak Jr. develops the first practical visible-spectrum (red) light-emitting diode. 1963 Kurt Schmidt invents the first high pressure sodium-vapor lamp. [18] 1972 M. George Craford invents the first yellow light-emitting diode. 1972 Herbert Paul Maruska and Jacques Pankove create the first violet light-emitting diode.
German inventor Karl Ferdinand Braun invented cathode ray oscilloscope (CRO). 1901: First transatlantic radio transmission by Guglielmo Marconi 1901: American engineer Peter Cooper Hewitt invented the Fluorescent lamp. 1904: English engineer John Ambrose Fleming invented the diode. 1906: American inventor Lee de Forest invented the triode. 1908
The first Light-Emitting Diode was created in 1927 by Russian inventor Oleg Losev, [1] and used silicon carbide as a semiconductor. However, electroluminescence as a phenomenon was discovered twenty years earlier by the English experimenter Henry Joseph Round of Marconi Labs , using the same crystal and a cat's-whisker detector .
In an organic light-emitting diode , the electroluminescent material composing the emissive layer of the diode is an organic compound. The organic material is electrically conductive due to the delocalization of pi electrons caused by conjugation over all or part of the molecule, and the material therefore functions as an organic semiconductor ...
The timeline of historic inventions is a chronological list of particularly significant technological inventions and their inventors, where known. [ a ] The dates in this article make frequent use of the units mya and kya , which refer to millions and thousands of years ago, respectively.
Thermionic (vacuum-tube) diodes and solid-state (semiconductor) diodes were developed separately, at approximately the same time, in the early 1900s, as radio receiver detectors. [9] Until the 1950s, vacuum diodes were used more frequently in radios because the early point-contact semiconductor diodes were less stable.
A set of modern LED flashlights. A flashlight or electric torch (Commonwealth English), usually shortened to torch, is a portable hand-held electric lamp.Formerly, the light source typically was a miniature incandescent light bulb, but these have been displaced by light-emitting diodes (LEDs) since the early 2000s.
William Sturgeon invented the electromagnet in 1825. [19] Electromagnets were then used in the first practical engineering application of electricity by William Fothergill Cooke and Charles Wheatstone who co-developed a telegraph system that used a number of needles on a board which were moved to point to letters of the alphabet. A five needle ...