May 25, 2022

The light bulb is an electrical device designed to produce light. For this purpose, different technologies can be used and have different possible uses.

Historical chronology

The following are the main events: 1802: Humphrey Davy demonstrates arc lamp operation in atmospheric air; 1835: James Bowman Lindsay shows an incandescent lamp lighting system; 1841: experimental arc lamps for public lighting are installed in Paris; 1856: the glassblower Heinrich Geissler creates the first electric arc inside a tube; 1867: Antoine Henri Becquerel proposes the first example of a fluorescent lamp; 1875: Henry Woodward patents the electric light bulb; 1876: Pavel Jabločkov, in Paris, invents the Yablochkov candle, the first arc lamp with carbon electrodes: vertical and parallel, the electrodes were connected as a bridge by a strip of graphite that surmounted them and allowed them to be lit; of practical use, it took advantage of the use of alternating current, which guaranteed uniform wear of the electrodes. The invention, which made the cost of electric lighting cheaper, spread to France and Great Britain starting from 1887 and was used for public lighting in Paris; 1879: Alessandro Cruto, researcher from Piossasco (TO), stimulated by a series of lectures held by Galileo Ferraris, devoted himself to the creation of a filament for incandescent light bulbs, succeeding, unique among the experimenters, in producing one with a positive coefficient (resistance which increases with increasing temperature), using a carbon filament immersed in an ethylene atmosphere. This allowed the bulb to shine for 500 hours compared to 40 reached by the Thomas Edison prototypes presented 6 months earlier. Cruto's great knowledge of carbon was due to his years of experimentation in an attempt to create synthetic diamonds. Despite having created a filament capable of surpassing that of the Americans, Cruto was unable to patent the invention on a worldwide scale, due to the lack of financiers. 1880: Nikola Tesla invents the incandescent lamp with carbon filament; 1881: Lewis Latimer patents the electric lamp; 1882: Lewis Latimer patents a global holder for electric light bulbs; 1890: Alexander Lodygin patents the use of tungsten filament in incandescent lamps; 1893: Nikola Tesla develops induction discharge lamps, without electrodes, powered at high frequency, and uses them to illuminate his own laboratory; 1894: Daniel McFarlan Moore invents the Moore tube, precursor of current discharge lamps; 1894: Arturo Malignani patents a system to create the vacuum in the bulb of the lamp and the fast (and less harmful for the workers) mass production of light bulbs; 1901: Peter Cooper Hewitt develops the mercury vapor discharge lamp; 1903: William David Coolidge commercially introduces the use of tungsten filament, which in the simple and then double spiral versions, has come down to the present day, surpassing the century of life; 1910: Lewis Latimer develops a new method for the production of carbon filaments for incandescent lamps which allows for longer lasting lamps; 1911: Georges Claude creates the neon lamp; 1924: The Phoebus cartel is formed, the first cartel of light bulb manufacturing companies; 1926: Edmund Germer patents the fluorescent lamp, which will be marketed starting from 1938 in the straight or annular tube versions with external ignition and stabilization circuit (ballast), and will appear in a compact version with E27 socket and electronic ballast incorporated in 1978 (the current so-called low consumption light bulbs); 1962: Nick Holonyak Jr. patents the first visible light LED light emitting semiconductor, which is commer