A gadget that uses electric power to produce visible light is called an electric light. It is the most prevalent type of artificial lighting and is crucial to contemporary life since it provides both interior lighting for buildings and external lighting for activities during the evening and at night. A lamp is a changeable part that generates light using electricity in technical parlance. Light bulbs, like the incandescent light bulb, are the common name for lamps. In order to fit into a light fixture's socket, lamps typically have a base made of ceramic, metal, glass, or plastic. A screw-thread base, two metal pins, two metal caps, or a bayonet cap can all be used to make the electrical connection to the socket.
Incandescent lamps, which produce light by heating a filament to a white-hot temperature with an electric current, gas-discharge lamps, which produce light by passing an electric arc through a gas, like fluorescent lamps, and LED lamps, which produce light by a flow of electrons across a semiconductor band gap, are the three main types of electric lighting.
People utilized candles, gas lights, oil lamps, and fires until electric illumination became widely used in the early 20th century. The first practical electric arc light was created by English chemist Humphry Davy in 1806 after he created the first incandescent light in 1802. Davy's arc lamp had been successfully commercialized by the 1870s and was being used to illuminate a lot of public areas. Commercial incandescent light bulbs became widely available in the 1880s thanks to the efforts of Joseph Swan and Thomas Edison, and by the early 20th century, these had totally supplanted arc lamps.
Since the initial demonstrations of arc lamps and the incandescent light bulb in the 19th century, the energy efficiency of electric lighting has dramatically grown. Modern electric light sources are available in a wide range of shapes and sizes that are suitable for a variety of uses. The majority of contemporary electric lighting is powered by centrally generated electricity, however it is also possible for lights to be powered by portable or standby generators or battery systems. When and when stationary lights fail, battery-powered lighting is frequently used in cars as well as flashlights or electric lanterns.
Types
the following electric lighting types:
A heated filament enclosed in glass makes up an incandescent light bulb.
Incandescent lights called halogen lamps employ fused quartz encasings to contain halogen gas.A solid-state lamp called an LED uses light-emitting diodes (LEDs) as its source of illumination.A arc lamp
Lamp made of carbon
searchlights and movie projectors both employ xenon arc lamps.
Arc lamp with mercury-xenon
Many video projectors employ UHP lamps, which are ultra-high-pressure mercury-vapor arc lamps.
Using an electric discharge to illuminate an ionized gas, a gas-discharge lamp produces light.
the following electric lighting types:
A heated filament enclosed in glass makes up an incandescent light bulb.
Incandescent lights called halogen lamps employ fused quartz encasings to contain halogen gas.
A solid-state lamp called an LED uses light-emitting diodes (LEDs) as its source of illumination.
A arc lam
The low-pressure sodium lamp is the most effective type of electric lighting. For all intents and purposes, it emits an orange-yellow light that is monochromatic, giving the impression that any lighted scene is also monochrome. It is typically only used for outdoor public illumination applications because of this. Astronomers like low-pressure sodium lights for public illumination because, unlike broadband or continuous spectra, their light pollution can be easily filtered.
a standard incandescent bulb
The carbon filament lamp that was launched around 1880 evolved into the contemporary incandescent light bulb, which was commercialized in the 1920s and has a coiled tungsten filament.
Only 3% of the energy supplied is transformed into useful light. Nearly all of the input energy converts to heat, which must then be evacuated from buildings in warm areas by ventilation or air conditioning, frequently using more energy. The heat byproduct has some use in colder climates where heating and illumination are necessary during the dark, gloomy winter months. Due to their poor energy efficiency, incandescent lights are being phased out in several nations.
In addition to standard light bulbs, there are a huge variety available, including low voltage, low power models that were once commonly employed as equipment components but have since been completely replaced by LEDs.
Halogen light
Halogen lamps are typically significantly smaller than typical incandescent lamps since a bulb temperature of more than 200 °C is typically required for successful functioning. Due to this, the majority of lightbulbs are made of aluminosilicate glass or fused silica (quartz). This is frequently enclosed inside of an extra glass layer. In case the inner envelope explodes while operating, the outer glass acts as a safety measure to contain hot glass shards and limit UV emission. Due to significant heat buildup at the contamination point, oily residue from fingerprints may cause a hot quartz envelope to break. Bare bulbs carry a higher danger of burns or fire, which is why certain locations forbid them unless they are enclosed by a luminaire.
Compact filaments, which are advantageous for effective optical control, are found in those made for 12- or 24-volt operation. Additionally, they outlive non-halogen varieties and have higher efficacies (lumens per watt). Throughout their lifespan, the light output is essentially constant.
A glass tube that houses mercury vapour or argon at low pressure makes up fluorescent lamps. The gases emit UV radiation when electricity is passed through the tube. The tubes' inside are covered with phosphors that, when exposed to UV photons, emit visible light. Compared to incandescent bulbs, they are significantly more efficient. They typically consume between a quarter and a third of the power of an incandescent to provide the same amount of light. Fluorescent lighting systems typically have a luminous efficacy of 50 to 100 lumens per watt, which is significantly higher than the efficacy of incandescent bulbs with a similar light output.
Because a ballast is needed to control the current through the lamp, fluorescent lamp fixtures are more expensive than incandescent lamp fixtures. However, the lower energy cost usually makes up for the higher initial cost. In homes, compact fluorescent lights are utilized as an energy-saving option because they come in the same common sizes as incandescent bulbs. Many fluorescent lights are categorized as hazardous trash because they contain mercury. Fluorescent lamps should be separated from other waste so they can be recycled or safely disposed of, and some jurisdictions have recycling laws that must be followed.
LED light
Since the 1970s, consumer electronics and professional audio equipment have frequently used solid-state light-emitting diodes (LEDs) as an indicator light. LEDs are currently employed in lighting applications like automotive headlights and brake lights, flashlights, and bicycle lights, as well as in decorative applications like holiday illumination, thanks to improvements in efficiency and output in the 2000s.
Indicator LEDs have a lifespan of up to 100,000 hours, whereas illumination LEDs are used much less sparingly and have lower lifespans as a result. For lighting designers, LED technology is advantageous due to its low power consumption, low heat generation, instantaneous on/off control, and, in the case of single-color LEDs, color constancy over the course of the diode's lifespan and comparatively low manufacturing costs. The temperature of the diode has a significant impact on LED lifetime. Operating an LED bulb under circumstances that raise its internal temperature can significantly reduce its lifespan.
Lamp made of carbon
Two carbon rod electrodes are used in carbon arc lamps, which are powered by current-limiting ballasts and placed outside. The rod tips are touched and then separated to create the electric arc. White-hot plasma is created between the rod tips by the succeeding arc. These lamps are more efficient than filament lamps, but because of the carbon rods' limited lifespan and need for regular adjustment while in operation, due to the arc's extreme heat. Because of their intensity, the lamps need to be shielded from direct sunlight and create a large amount of UV light when used indoors.
The carbon arc was the first useful electric light, developed by Humphry Davy about 1805. It was employed commercially for large building and street lighting starting in the 1870s until it was replaced by the incandescent light in the early 20th century. High power and high intensity white light are produced by carbon arc lamps. They also function as a single point of light. They were still in use after World War II for a few specific uses that needed these characteristics, such as searchlights, stage lighting, and movie projectors.
charge-based lamp
A glass or silica envelope housing two metal electrodes spaced apart by a gas makes up a discharge lamp. Neon, argon, xenon, sodium, metal halide, and mercury are some of the gases used. Although the term "arc lamp" typically refers to carbon arc lamps, more contemporary forms of gas discharge lamp are more commonly referred to as discharge lamps. The fundamental operating mechanism is much the same as the carbon arc lamp. Some discharge lamps employ extremely high voltage to ignite the arc. This calls for the use of an igniter electrical circuit, which is a component of the electrical ballast circuitry.
The internal resistance of the lamp decreases to a low level once the arc is struck, and the ballast restricts the current to the operational current. Without a ballast, the light would quickly burn out from an excessive current flow.
A little quantity of neon is present in some lamp types, allowing striking at running voltage without the need for an external ignition circuitry. This is how low-pressure sodium lamps work. Where cost is a deciding factor, such as in street lighting, the simplest ballasts, which consist only of an inductor, are used.
Advanced electronic ballasts may be created to keep the light output consistent throughout the lamp's lifespan, drive the lamp with a square wave to keep the output flicker-free, and shut off in the event of specific faults.
Formal aspects
Standardized form codes and socket names are used to specify many lamp units, or light bulbs. The usual size for these kinds of light bulbs is "A19/A60 E26/E27," and incandescent bulbs and their retrofit replacements are frequently designated as such. In this illustration, the "A" parameters designate the size and shape of the lightbulb, and the "E" parameters designate the dimensions and features of the Edison screw base.
Life expectancy of lamps
The median life of the lamps—the number of hours of operation at which half of them fail—is used to define the life expectancy for several different types of lamps. Lamp life can vary by up to 25% due to production tolerances as little as 1%, thus generally speaking, some lamps will fail considerably sooner than their rated life expectancy while others will survive a lot longer. Lamp life for LEDs is the period of operation during which 50% of the bulbs have suffered a 70% reduction in light output.
Additionally, some bulb types are delicate to switching cycles. Expect a substantially shorter lamp life than what is stated on the box in places with frequent switching, such as toilets. Particularly sensitive to switching cycles are compact fluorescent lights.
public illumination
Cities may easily be seen at night from the air and from space thanks to the overall amount of artificial light, notably from street lights. Astronomers and other people are burdened by light pollution that is caused by this light.
applications besides illumination
Incubators, fast food restaurants, and toys like the Kenner Easy-Bake Oven are just a few examples of places where electric bulbs can be employed as heat sources.
Tungsten filament lamps have long been employed as quick-acting thermistors in electronic circuits because of their nonlinear resistance properties. Typical applications include:
Sine wave oscillators' stabilization
Protection for tweeters in speaker enclosures; when a tweeter receives an excessive amount of current, the light lights rather than the tweeter being damaged.
telephones with automatic volume control
The Turkish AK Party's logo is a stylized representation of a lightbulb.
Circuit diagrams
Lamps have two primary sorts of symbols in circuit diagrams that represent their various functionalities. As follows:
Typically, the cross in a circle denotes an indicator lamp. (1986) (ANSI/IEEE Std 315A)
Typically, the cross in a circle denotes an indicator lamp. (1986) (ANSI/IEEE Std 315A)
a dent in a circle that is semicircular and typically portrays a lamp as a source of light or illumination.
a dent in a circle that is semicircular and typically portrays a lamp as a source of light or illumination.
A lightbulb, and particularly one that seems lighting over someone's head, is a symbol of inspiration in Western culture.
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