The incandescent lamp — the illuminant, an artificial light source. Light is let out by a heated metal spiral at course through it electric current.In 1809 Englishman Delaryu builds the first incandescent lamp (with a platinum spiral)In 1838 Belgian Zhobar invents the coal incandescent lamp.In 1854 the German inventor Heinrich Gebel developed the first "modern" lamp: the charred bamboo thread in the vacuumized vessel. In the next 5 years he developed that many call the first practical lamp.On July 11, 1874 the Russian engineer Alexander Nikolaevich Lodygin took out the patent behind number 1619 on a nitevy lamp. As the filament it used the coal core placed in the vacuumized vessel.The English inventor Joseph Wilson Svan took out in 1878 the British patent for a lamp with coal fiber. In its lamps fiber was in the rarefied oxygen atmosphere that allowed to receive very bright light.In the second half of the 1870th years the American inventor Thomas Edison carries out research work in which he tries various metals as a thread. In 1879 it patents a lamp with a platinum thread. In 1880 it comes back to coal fiber and creates a lamp with time of life of 40 hours. At the same time Edison invented a cartridge, a socle and the switch. Despite so short time of life of its lamp force out gas lighting used until then.In the 1890th years Lodygin invents some types of lamps with metallic threads of heat.In 1906 Lodygin sells the patent for a tungsten thread of the General Electric company. Because of the high cost of tungsten the patent finds only limited application.In 1910 William David Coolidge invents the improved method of production of a tungsten thread. Subsequently the tungsten thread forces out all other types of threads.The remaining problem in vacuum was solved with fast evaporation of a thread by the American scientist Irving Lengmyur who, working since 1909 in General Electric firm, thought up to fill flasks of lamps with inert gas that significantly increased time of life of lamps.
