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Electric Lights
An electric light, lamp, or light bulb is an electrical component that produces light. It is the most common form of artificial lighting. Lamps usually have a base made of ceramic, metal, glass, or plastic, which secures the lamp in the socket of a light fixture, which is often called a "lamp" as well. The electrical connection to the socket may be made with a screw-thread base, two metal pins, two metal caps or a bayonet cap. 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, such as fluorescent lamps, and LED lamps, which produce light by a flow of electrons across a band gap in a semiconductor. Before electric lighting became common in the early 20th century, people used candles, gas lights, oil lamps, and fires. Vasily Vladimirovich Petrov developed the first persistent electric arc in 1802, and En ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Fixture
A light fixture (US English), light fitting (UK English), or luminaire is an electrical device containing an electric lamp that provides illumination. All light fixtures have a fixture body and one or more lamps. The lamps may be in sockets for easy replacement—or, in the case of some LED fixtures, hard-wired in place. Fixtures may also have a switch to control the light, either attached to the lamp body or attached to the power cable. Permanent light fixtures, such as dining room chandeliers, may have no switch on the fixture itself, but rely on a wall switch. Fixtures require an electrical connection to a power source, typically AC mains power, but some run on battery power for camping or emergency lights. Permanent lighting fixtures are directly wired. Movable lamps have a plug and cord that plugs into a wall socket. Light fixtures may also have other features, such as reflectors for directing the light, an aperture (with or without a lens), an outer shell or housing f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasily Vladimirovich Petrov
Vasily Vladimirovich Petrov (russian: Василий Владимирович Петров) ( – 15 August 1834) was a Russian experimental physicist, self-taught electrical technician, academician of Russian Academy of Sciences (since 1809; Corresponding member since 1802). Vasily Petrov was born in the town of Oboyan (of the Belgorod Province, currently Kursk Oblast of Russia) in the family of a priest. He studied at a public school in Kharkov, and then at the St. Petersburg Teacher's College. In 1788, he gained a position as mathematics and physics teacher at Kolyvansko-Voskresenskoe College of Mining, in the town of Barnaul. In 1791, he was transferred to Saint Petersburg to teach mathematics and Russian at the military Engineering College, in the Izmailovsky regiment. In 1793, Petrov was invited to teach mathematics and physics at the St. Petersburg Medical and Surgery School, at the military hospital. In 1795, he was promoted to the rank of 'Extraordinary Professor'. Du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire
Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. At a certain point in the combustion reaction, called the ignition point, flames are produced. The ''flame'' is the visible portion of the fire. Flames consist primarily of carbon dioxide, water vapor, oxygen and nitrogen. If hot enough, the gases may become ionized to produce Plasma (physics), plasma. Depending on the substances alight, and any impurities outside, the color of the flame and the fire's Intensity (heat transfer), intensity will be different. Fire in its most common form can result in conflagration, which has the potential to cause physical damage through burning. Fire is an important process that affects ecological systems around the globe. The positive effects of fire include stimulating growth and maintaining various ecological systems. Its negative effects include hazard to life and pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oil Lamp
An oil lamp is a lamp used to produce light continuously for a period of time using an oil-based fuel source. The use of oil lamps began thousands of years ago and continues to this day, although their use is less common in modern times. They work in the same way as a candle but with fuel that is liquid at room temperature, so that a container for the oil is required. A textile wick drops down into the oil, and is lit at the end, burning the oil as it is drawn up the wick. Oil lamps are a form of lighting, and were used as an alternative to candles before the use of electric lights. Starting in 1780, the Argand lamp quickly replaced other oil lamps still in their basic ancient form. These in turn were replaced by the kerosene lamp in about 1850. In small towns and rural areas the latter continued in use well into the 20th century, until such areas were finally electrified and light bulbs could be used. Sources of fuel for oil lamps include a wide variety of plants such as n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Lighting
Gas lighting is the production of artificial light from combustion of a gaseous fuel, such as hydrogen, methane, carbon monoxide, propane, butane, acetylene, ethylene, coal gas (town gas) or natural gas. The light is produced either directly by the flame, generally by using special mixes (typically propane or butane) of illuminating gas to increase brightness, or indirectly with other components such as the gas mantle or the limelight, with the gas primarily functioning as a heat source for the incandescence of the gas mantle or lime. Before electricity became sufficiently widespread and economical to allow for general public use, gas was the most prevalent method of outdoor and indoor lighting in cities and suburbs, areas where the infrastructure for distribution of the gaseous fuel was practical. When gas lighting was prevalent, the most common fuels for gas lighting were wood gas, coal gas and, in limited cases, water gas. Early gas lights were ignited manually by lampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candle
A candle is an ignitable wick embedded in wax, or another flammable solid substance such as tallow, that provides light, and in some cases, a fragrance. A candle can also provide heat or a method of keeping time. A person who makes candles is traditionally known as a chandler. Various devices have been invented to hold candles, from simple tabletop candlesticks, also known as candle holders, to elaborate candelabra and chandeliers. For a candle to burn, a heat source (commonly a naked flame from a match or lighter) is used to light the candle's wick, which melts and vaporizes a small amount of fuel (the wax). Once vaporized, the fuel combines with oxygen in the atmosphere to ignite and form a constant flame. This flame provides sufficient heat to keep the candle burning via a self-sustaining chain of events: the heat of the flame melts the top of the mass of solid fuel; the liquefied fuel then moves upward through the wick via capillary action; the liquefied fuel finally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glass. Its electrical resistivity and conductivity, resistivity falls as its temperature rises; metals behave in the opposite way. Its conducting properties may be altered in useful ways by introducing impurities ("doping (semiconductor), doping") into the crystal structure. When two differently doped regions exist in the same crystal, a semiconductor junction is created. The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called "metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second-most common s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band Gap
In solid-state physics, a band gap, also called an energy gap, is an energy range in a solid where no electronic states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference (in electron volts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote a valence electron bound to an atom to become a conduction electron, which is free to move within the crystal lattice and serve as a charge carrier to conduct electric current. It is closely related to the HOMO/LUMO gap in chemistry. If the valence band is completely full and the conduction band is completely empty, then electrons cannot move within the solid because there are no available states. If the electrons are not free to move within the crystal lattice, then there is no generated current due to no net charge carrier mobility. However, if some electrons transfer from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LED Lamp
An LED lamp or LED light bulb is an electric light that produces light using light-emitting diodes (LEDs). LED lamps are significantly more energy-efficient than equivalent incandescent lamps and can be significantly more efficient than most fluorescent lamps. The most efficient commercially available LED lamps have efficiencies of 200 lumen per watt (Lm/W). Commercial LED lamps have a lifespan many times longer than incandescent lamps. LED lamps require an electronic LED driver circuit to operate from mains power lines, and losses from this circuit means that the efficiency of the lamp is lower than the efficiency of the LED chips it uses. The driver circuit may require special features to be compatible with lamp dimmers intended for use on incandescent lamps. Generally the current waveform contains some amount of distortion, depending on the luminaires’ technology. The LED lamp market is projected to grow from US$75.8 billion in 2020 and increasing to US$160 billion in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescent Lamp
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than an incandescent lamp. The typical luminous efficacy of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output. For comparison, the luminous efficacy of an incandescent bulb may only be 16 lumens per watt. Fluorescent lamp fixtures are more costly than incandescent lamps because, among other things, they require a ballast to regulate current through the lamp, but the initial cost is offset by a much lower running cost. Compact fluorescent lamps are now available in the same popular sizes as incand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Arc
An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The electric current, current through a normally Electrical conductance, nonconductive medium such as air produces a plasma (physics), plasma; the plasma may produce visible light. An arc discharge is characterized by a lower voltage than a glow discharge and relies on thermionic emission of electrons from the electrodes supporting the arc. An archaic term is voltaic arc, as used in the phrase "voltaic arc lamp". Techniques for arc suppression can be used to reduce the duration or likelihood of arc formation. In the late 19th century, Arc lamp, electric arc lighting was in wide use for Street light#Arc lamps, public lighting. Some low-pressure electric arcs are used in many applications. For example, fluorescent lamp, fluorescent tubes, mercury, sodium, and metal-halide lamps are used for lighting; xenon arc lamps have been used for movie projectors. Electric a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
