A light bulb is an artificial light source. The value of this invention was included into ten the greatest discoveries and mankind inventions. The bulb appeared in people’s life not long ago, at the end of the XIX century. At first, lighting appeared in the streets of the cities and then it entered the houses. Today, it is hard to imagine the life of the civilized person without electric light. Such an invention caused huge consequences. The electricity made a revolution in an energetics, having forced the industry to change considerably. The incandescent bulb is an electric light source in which the transformation of electric energy to the light results from incandescence of the refractory conductor by an electric current. In 1879, the American inventor T.A. Edison created a rather durable design of the incandescent lamp with a coal thread, convenient for industrial production. Besides, he expanded the practical application of electricity which was even more important than the invention of a light bulb.
In the XIX century, there were two types of bulbs – arc and incandescent lamps. Arc bulbs, which luminescence was based on such a phenomenon as a volt arch, appeared the first. If two wires are connected to a strong current and moved apart, there will be a luminescence between their ends. For the first time, this phenomenon was observed by the Russian scientist Vasily Petrov in 1803. The Englishman Devi also described such an effect, but only in 1810. The application of the volt arch as a source of lighting was described by both scientists. However, arc lamps had an inconvenience – in the process of burning out of electrodes, they should be moved constantly to each other. An exceeding distance between them caused light blinking. In 1844 the Frenchman Foucault developed the first arc lamp in which the length of an arch could be regulated manually. Four years later this invention was applied to illumination of one of the areas of Paris. In 1876, the Russian engineer Yablochkov improved the construction – he replaced the electrodes with pieces of coal, installed parallel to each other so that the distance between the ends always remained invariable.
In 1879, the American inventor Edison undertook the construction improvement. He came to a conclusion that the suitable materials for a thread as well as the rarefied space around are necessary for a long and bright luminescence of a bulb. He achieved it as a result of a huge scientific and experimental work, having been carried out by Edison for many years. The inventor tried an uncountable set of various materials. He made about 6000 experiments only over a bamboo. A charred thread from one sort of a Japanese bamboo appeared suitable. Edison managed to achieve the replacement of coal lamps existing in his time with a resistance of 1 — 4 ohm by coal lamps with a resistance of hundred and even thousands ohms. At last, tt resolved a notorious problem of crushing of electric light. The researches cost 100 thousand dollars to the American. Edison gradually began to use metals for a thread and he stopped on the charred bamboo fibers. The inventor showed his results in the presence of three thousand audience. He introduced publicly the electric bulbs developed by him, having shined with them not only the house but also some neighboring streets. Edison’s bulb became the first bulb with a long service life, which was suitable for a mass production.
Edison’s system of electric illumination evoked all people’s admiration at the World Fair in Paris in 1881. It is curious that the same year the French physicist Marseille Depre made a report on the experiments on electric power transfer on long distances at the world congress of electricians.
In Menlo-park, the State of New York, Edison constructed a small power plant for needs of his own laboratory; however, it appeared to produce energy more than it was required for him, so the inventor agreed to sell it to his neighbors-farmers, having stretched the wires. These people, probably, also did not recognize that they became the first-ever paid consumers of electricity. Edison never wanted to be a businessman, but often, needing something for the work, he opened a small production, which was expanded then to huge scales in Menlo-park and started to exist separately.
Edison was one of the first (almost at the same time with Siemens, 1879), who started an electrification of the railway transport. The Electric Edison Road of 500 m was constructed in Menlo-park in 1880. The train, consisting of an electric locomotive and four carriages, was set in motion by the electric power, which was delivered through underground cables from the central electrical Menlo-park station. In 1882, Edison started the construction of lighting station in New York on 5500 lamps. To save copper, he invented a three-wire system of distribution of the direct current, giving over 50% of economy. Edison’s way has been applied until now.
Edison’s lighting system was capable to compete with gas illumination of that time. For the expansion of practical application of electricity, it was not less important than the invention of a light bulb. In 1873, after thousands of experiments he created a light bulb (with a coal thread), which burned 40 hours. Edison constructed generators of a direct current, a power line and electric networks, and later – a three-wire system. In 1882, Edison started the first central power plant in New York. It was the beginning of the lighting industry in America.