An incandescent lamp is a light source consisting of a transparent vacuumized vessel, which can be filled with an inert gas and an incandescent body placed in it. Such a lamp emits visible light due to the heating by electric current of the incandescent body, which, as a rule, is a spiral made of tungsten alloys.
Arc lamps
The progenitor of the incandescent lamp can be considered arc lamps, which appeared somewhat earlier. The light source in such lamps was the voltaic arc phenomenon. It is believed that the first to observe this phenomenon was the Russian scientist Vasily Petrov in 1803. To obtain a voltaic arc, he used a large battery of cells and 2 rods of charcoal. Having passed a current through the rods, he connected their ends and pushed them apart, receiving an arc. In 1810, the English physicist Devi did the same. Both scientists wrote scientific articles in which they argued that the voltaic arc could have practical applications for lighting purposes.
Coal-based arc lamps had serious drawbacks: the rods burned out very quickly, they had to be constantly moved towards each other as they burned. Despite this, many scientists continued to work on improving arc lamps, but they did not manage to completely get rid of the disadvantages inherent in arc lamps.
Incandescent lamps
It is believed that the first incandescent lamp was made in 1809 by the scientist Delarue; platinum wire became the incandescent body in that lamp. The lamp turned out to be impractical and short-lived, so it was quickly forgotten about it. The next step in the widespread distribution of incandescent lamps was a patent for a filament lamp, obtained by the Russian inventor Lodygin in 1874. This lamp consisted of an evacuated vessel with an incandescent body in the form of a thin rotor carbon rod. But this lamp was still very far from being perfect, although it received little practical use.
This continued until the famous and talented American inventor Edison joined the process in the mid-1870s. The inventor got down to business with his usual scope. In search of the most optimal material for the thread, more than 6,000 different compounds and substances were tested, for which a huge sum of 100 thousand dollars was spent at that time. As a result of the experiments, he settled on a thread of charred bamboo fibers and made several dozen lamps on their basis.
But lamps that used bamboo filaments were very expensive to manufacture, so research continued. In the final version, the incandescent lamp consisted of: an evacuated glass cap, in which a cotton-based thread made by means of complex operations was placed between two platinum electrodes, all this was put on a base with contacts. The production of such lamps was very complex and expensive, which did not prevent Edison from making them for several decades.
All this time, Lodygin continued his work, thanks to which, in the 1890s, he managed to invent and patent several types of lamps, in which filaments of refractory metals became incandescent bodies. In 1906, he sold a patent for a tungsten filament to the American company General Electric and built a plant in the United States for the electrochemical production of titanium, chromium and tungsten. The sold patent is of limited use due to the high cost of tungsten.
In 1909, Irving Langmuir, a specialist in the field of vacuum technology from General Electric, by introducing heavy noble gases into the flasks, increases the life of the lamps. In 1910, tungsten filament, thanks to the invention of an improved manufacturing method by William D. Coolidge, supplants all other types of filaments. Incandescent lamps are widely used in practice, which has survived to this day.
