Modern electric light sources come in a profusion of types and sizes adapted to many applications.
The energy efficiency of electric lighting has increased radically since the first demonstration of arc lamps and the incandescent light bulb of the 19th century. The development of a steadily glowing filament suitable for interior lighting took longer, but by the early twentieth century inventors had successfully developed options, replacing the arc light with incandescents. By the 1870s, Davy's arc lamp had been successfully commercialized, and was used to light many public spaces. Humphry Davy developed the first incandescent light in 1802, followed by the first practical electric arc light in 1806. The three main categories of electric lights are incandescent lamps, which produce light by a filament heated white-hot by electric current, gas-discharge lamps, which produce light by means of an electric arc through a gas, and LED lamps, which produce light by a flow of electrons across a band gap in a semiconductor.īefore electric lighting became common in the early 20th century, people used candles, gas lights, oil lamps, and fires. The electrical connection to the socket may be made with a screw-thread base, two metal pins, two metal caps or a bayonet cap. Lamps usually have a base made of ceramic, metal, glass or plastic, which secures the lamp in the socket of a light fixture. Compact lamps are commonly called light bulbs for example, the incandescent light bulb. In technical usage, a replaceable component that produces light from electricity is called a lamp. It is the most common form of artificial lighting and is essential to modern society, providing interior lighting for buildings and exterior light for evening and nighttime activities. An electric light is a device that produces visible light from electric current.
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