Misplaced Pages

#658341

56-617: In common parlance, electric power is the production and delivery of electrical energy, an essential public utility in much of the world. Electric power is usually produced by electric generators , but can also be supplied by sources such as electric batteries . It is usually supplied to businesses and homes (as domestic mains electricity ) by the electric power industry through an electrical grid . Electric power can be delivered over long distances by transmission lines and used for applications such as motion , light or heat with high efficiency . Electric power, like mechanical power ,

112-668: A continuous spectrum . Incandescent bulbs are highly inefficient, in that just 2–5% of the energy consumed is emitted as visible, usable light . The remaining 95% is lost as heat . In warmer climates, the emitted heat must then be removed, putting additional pressure on ventilation or air conditioning systems. In colder weather, the heat byproduct has some value, and has been successfully harnessed for warming in devices such as heat lamps . Incandescent bulbs are nonetheless being phased out in favor of technologies like CFLs and LED bulbs in many countries due to their low energy efficiency. The European Commission estimated in 2012 that

168-420: 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 . The energy efficiency of electric lighting has increased radically since the first demonstration of arc lamps and the incandescent light bulb of

224-402: A grow light to aid in plant growth especially in indoor hydroponics and aquatic plants with recent research into the most effective types of light for plant growth. Due to their nonlinear resistance characteristics, tungsten filament lamps have long been used as fast-acting thermistors in electronic circuits. Popular uses have included: In Western culture, a lightbulb — in particular,

280-581: A monochromatic orange-yellow light, which gives a similarly monochromatic perception of any illuminated scene. For this reason, it is generally reserved for outdoor public lighting applications. Low-pressure sodium lights are favoured for public lighting by astronomers, since the light pollution that they generate can be easily filtered, contrary to broadband or continuous spectra. Many lamp units, or light bulbs, are specified in standardized shape codes and socket names. Incandescent bulbs and their retrofit replacements are often specified as " A19 /A60 E26 /E27",

336-484: A better design. The rivalry between Swan and Edison eventually led to a merger, forming the Edison and Swan Electric Light Company . By the early twentieth century these had completely replaced arc lamps . The turn of the century saw further improvements in bulb longevity and efficiency, notably with the introduction of the tungsten filament by William D. Coolidge , who applied for a patent in 1912. This innovation became

392-429: A century of continuous and incremental improvement, including numerous designs, patents, and resulting intellectual property disputes, to get from these early experiments to commercially produced incandescent light bulbs in the 1920s. In 1840, Warren de la Rue enclosed a platinum coil in a vacuum tube and passed an electric current through it, thus creating one of the world's first electric light bulbs . The design

448-433: A circuit from a component is defined to have a negative sign. Thus passive components have positive power consumption, while power sources have negative power consumption. This is called the passive sign convention . In the case of resistive (Ohmic, or linear) loads, the power formula ( P = I·V ) and Joule's first law ( P = I^2·R ) can be combined with Ohm's law ( V = I·R ) to produce alternative expressions for

504-449: A common size for those kinds of light bulbs. In this example, the "A" parameters describe the bulb size and shape within the A-series light bulb while the "E" parameters describe the Edison screw base size and thread characteristics. Common comparison parameters include: Less common parameters include color rendering index (CRI). Life expectancy for many types of lamp is defined as

560-414: A complete ban on incandescent bulbs would contribute 5 to 10 billion euros to the economy and save 15 billion metric tonnes of carbon dioxide emissions . Halogen lamps are usually much smaller than standard incandescent lamps, because for successful operation a bulb temperature over 200 °C is generally necessary. For this reason, most have a bulb of fused silica (quartz) or aluminosilicate glass. This

616-505: A complete cycle of the AC waveform, results in net transfer of energy in one direction is known as real power (also referred to as active power). The amplitude of that portion of energy flow (power) that results in no net transfer of energy but instead oscillates between the source and load in each cycle due to stored energy, is known as the absolute value of reactive power . The product of the RMS value of

SECTION 10

#1732858473659

672-422: A glass or silica envelope containing two metal electrodes separated by a gas. Gases used include, neon , argon , xenon , sodium , metal halides , and mercury . The core operating principle is much the same as the carbon arc lamp, but the term "arc lamp" normally refers to carbon arc lamps, with more modern types of gas discharge lamp normally called discharge lamps. With some discharge lamps, very high voltage

728-572: A loop of wire, or disc of copper between the poles of a magnet . For electric utilities , it is the first process in the delivery of electricity to consumers. The other processes, electricity transmission , distribution , and electrical energy storage and recovery using pumped-storage methods are normally carried out by the electric power industry . Electricity is mostly generated at a power station by electromechanical generators , driven by heat engines heated by combustion , geothermal power or nuclear fission . Other generators are driven by

784-421: A source or a load, depending on the voltage and current through them. For example, a rechargeable battery acts as a source when it provides power to a circuit, but as a load when it is connected to a battery charger and is being recharged. If conventional current flows through the device in a direction from higher potential (voltage) to lower potential, so positive charge moves from the positive (+) terminal to

840-529: A standard for incandescent bulbs for many years. In 1910, Georges Claude introduced the first neon light, paving the way for neon signs which would become ubiquitous in advertising. In 1934, Arthur Compton , a renowned physicist and GE consultant, reported to the GE lamp department on successful experiments with fluorescent lighting at General Electric Co., Ltd. in Great Britain (unrelated to General Electric in

896-905: Is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output. Fluorescent lamp fixtures are more costly than incandescent lamps, because they require a ballast to regulate the current through the lamp, but the lower energy cost typically offsets the higher initial cost. Compact fluorescent lamps are available in the same popular sizes as incandescent lamps and are used as an energy-saving alternative in homes. Because they contain mercury, many fluorescent lamps are classified as hazardous waste . The United States Environmental Protection Agency recommends that fluorescent lamps be segregated from general waste for recycling or safe disposal, and some jurisdictions require recycling of them. The solid-state light-emitting diode (LED) has been popular as an indicator light in consumer electronics and professional audio gear since

952-506: Is a scalar since it is the surface integral of the Poynting vector . 2021 world electricity generation by source. Total generation was 28 petawatt-hours . The fundamental principles of much electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday . His basic method is still used today: electric current is generated by the movement of

1008-421: Is called power factor and is a number always between −1 and 1. Where the currents and voltages have non-sinusoidal forms, power factor is generalized to include the effects of distortion. Electrical energy flows wherever electric and magnetic fields exist together and fluctuate in the same place. The simplest example of this is in electrical circuits, as the preceding section showed. In the general case, however,

1064-465: Is often sealed inside an additional layer of glass. The outer glass is a safety precaution, to reduce ultraviolet emission and to contain hot glass shards should the inner envelope explode during operation. Oily residue from fingerprints may cause a hot quartz envelope to shatter due to excessive heat buildup at the contamination site. The risk of burns or fire is also greater with bare bulbs, leading to their prohibition in some places, unless enclosed by

1120-557: Is sufficient for cities to be easily visible at night from the air, and from space. External lighting grew at a rate of 3–6 percent for the later half of the 20th century and is the major source of light pollution that burdens astronomers and others with 80% of the world's population living in areas with night time light pollution. Light pollution has been shown to have a negative effect on some wildlife. Electric lamps can be used as heat sources, for example in incubators , as infrared lamps in fast food restaurants and toys such as

1176-407: Is the deciding factor, such as street lighting. More advanced electronic ballasts may be designed to maintain constant light output over the life of the lamp, may drive the lamp with a square wave to maintain completely flicker-free output, and shut down in the event of certain faults. The most efficient source of electric light is the low-pressure sodium lamp. It produces, for all practical purposes,

SECTION 20

#1732858473659

1232-443: 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 mount . The three main categories of electric lights are incandescent lamps, which produce light by

1288-648: Is the most important form of artificial light. Electrical energy is used directly in processes such as extraction of aluminum from its ores and in production of steel in electric arc furnaces . Reliable electric power is essential to telecommunications and broadcasting. Electric power is used to provide air conditioning in hot climates, and in some places, electric power is an economically competitive energy source for building space heating. The use of electric power for pumping water ranges from individual household wells to irrigation and energy storage projects. Public utility Too Many Requests If you report this error to

1344-644: Is the rate of doing work , measured in watts , and represented by the letter P . The term wattage is used colloquially to mean "electric power in watts". The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every t seconds passing through an electric potential ( voltage ) difference of V is: Work done per unit time = ℘ = W t = W Q Q t = V I {\displaystyle {\text{Work done per unit time}}=\wp ={\frac {W}{t}}={\frac {W}{Q}}{\frac {Q}{t}}=VI} where: I.e., Electric power

1400-410: Is transformed to other forms of energy when electric charges move through an electric potential difference ( voltage ), which occurs in electrical components in electric circuits. From the standpoint of electric power, components in an electric circuit can be divided into two categories: If electric current is forced to flow through the device in the direction from the lower electric potential to

1456-615: Is used to strike the arc. This requires an electrical circuit called an igniter, which is part of the electrical ballast circuitry. After the arc is struck, the internal resistance of the lamp drops to a low level, and the ballast limits the current to the operating current. Without a ballast, excess current would flow, causing rapid destruction of the lamp. Some lamp types contain a small amount of neon, which permits striking at normal running voltage with no external ignition circuitry. Low-pressure sodium lamps operate this way. The simplest ballasts are just an inductor, and are chosen where cost

1512-415: Is useful for lighting designers , because of its low power consumption, low heat generation, instantaneous on/off control, and in the case of single color LEDs, continuity of color throughout the life of the diode and relatively low cost of manufacture. LED lifetime depends strongly on the temperature of the diode. Operating an LED lamp in conditions that increase the internal temperature can greatly shorten

1568-406: The kinetic energy of flowing water and wind. There are many other technologies that are used to generate electricity such as photovoltaic solar panels. A battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery (or " voltaic pile ") in 1800 by Alessandro Volta and especially since

1624-437: The 1870s for large building and street lighting until it was superseded in the early 20th century by the incandescent light. Carbon arc lamps operate at high power and produce high intensity white light. They also are a point source of light. They remained in use in limited applications that required these properties, such as movie projectors , stage lighting , and searchlights , until after World War II. A discharge lamp has

1680-509: The 1900s the Phoebus cartel formed in an attempt to reduce the life of electric light bulbs, an example of planned obsolescence . Some types of lamp are also sensitive to switching cycles. Rooms with frequent switching, such as bathrooms, can expect much shorter lamp life than what is printed on the box. Compact fluorescent lamps are particularly sensitive to switching cycles. The total amount of artificial light (especially from street light )

1736-455: The 1970s. In the 2000s, efficacy and output have risen to the point where LEDs are now being used in lighting applications such as car headlights and brake lights, in flashlights and bicycle lights, as well as in decorative applications, such as holiday lighting. Indicator LEDs are known for their extremely long life, up to 100,000 hours, but lighting LEDs are operated much less conservatively, and consequently have shorter lives. LED technology

Electric power - Misplaced Pages Continue

1792-504: The 19th century. Modern electric light sources come in a profusion of types and sizes adapted to many applications. Most modern electric lighting is powered by centrally generated electric power, but lighting may also be powered by mobile or standby electric generators or battery systems. Battery -powered light is often reserved for when and where stationary lights fail, often in the form of flashlights or electric lanterns , as well as in vehicles. Before electric lighting became common in

1848-532: The Kenner Easy-Bake Oven . Lamps can also be used for light therapy to deal with such issues as vitamin D deficiency , skin conditions such as acne and dermatitis , skin cancers , and seasonal affective disorder . Lamps which emit a specific frequency of blue light are also used to treat neonatal jaundice with the treatment which was initially undertaken in hospitals being able to be conducted at home. Electric lamps can also be used as

1904-552: The United States). Stimulated by this report, and with all of the key elements available, a team led by George E. Inman built a prototype fluorescent lamp in 1934 at General Electric 's Nela Park (Ohio) engineering laboratory. This was not a trivial exercise; as noted by Arthur A. Bright, "A great deal of experimentation had to be done on lamp sizes and shapes, cathode construction, gas pressures of both argon and mercury vapor, colors of fluorescent powders, methods of attaching them to

1960-482: The Wikimedia System Administrators, please include the details below. Request from 172.68.168.132 via cp1112 cp1112, Varnish XID 391286302 Upstream caches: cp1112 int Error: 429, Too Many Requests at Fri, 29 Nov 2024 05:34:33 GMT Light bulb This is an accepted version of this page An electric light , lamp , or light bulb is an electrical component that produces light . It

2016-466: The amount of power that is dissipated: ℘ = I V = I 2 R = V 2 R {\displaystyle \wp =IV=I^{2}R={\frac {V^{2}}{R}}} where R is the electrical resistance . In alternating current circuits, energy storage elements such as inductance and capacitance may result in periodic reversals of the direction of energy flow. The portion of energy flow (power) that, averaged over

2072-522: The apparent power, when the current and voltage are both sinusoids with a known phase angle θ between them: (real power) = (apparent power) cos ⁡ θ {\displaystyle {\text{(real power)}}={\text{(apparent power)}}\cos \theta } (reactive power) = (apparent power) sin ⁡ θ {\displaystyle {\text{(reactive power)}}={\text{(apparent power)}}\sin \theta } The ratio of real power to apparent power

2128-416: The carbon rods are short-lived and require constant adjustment in use, as the intense heat of the arc erodes them. The lamps produce significant ultraviolet output, they require ventilation when used indoors, and due to their intensity they need protection from direct sight. Invented by Humphry Davy around 1805, the carbon arc was the first practical electric light. It was used commercially beginning in

2184-412: The direction of the voltage periodically reverses, but the current always flows from the higher potential to the lower potential side. Since electric power can flow either into or out of a component, a convention is needed for which direction represents positive power flow. Electric power flowing out of a circuit into a component is arbitrarily defined to have a positive sign, while power flowing into

2240-444: The early 20th century, people used candles , gas lights , oil lamps , and fires . In 1799–1800, Alessandro Volta created the voltaic pile , the first electric battery. Current from these batteries could heat copper wire to incandescence. Vasily Vladimirovich Petrov developed the first persistent electric arc in 1802, and English chemist Humphry Davy gave a practical demonstration of an arc light in 1806. It took more than

2296-533: The groundwork for future innovations such as those by Thomas Edison. The late 1870s and 1880s were marked by intense competition and innovation, with inventors like Joseph Swan in the UK and Thomas Edison in the US independently developing functional incandescent lamps. Swan's bulbs, based on designs by William Staite, were successful, but the filaments were too thick. Edison worked to create bulbs with thinner filaments, leading to

Electric power - Misplaced Pages Continue

2352-412: The higher, so positive charges move from the negative to the positive terminal, work will be done on the charges, and energy is being converted to electric potential energy from some other type of energy, such as mechanical energy or chemical energy . Devices in which this occurs are called active devices or power sources ; such as electric generators and batteries. Some devices can be either

2408-461: The home if broken and widespread problems with proper disposal of mercury-containing bulbs. In its modern form, the incandescent light bulb consists of a coiled filament of tungsten sealed in a globular glass chamber, either a vacuum or full of an inert gas such as argon . When an electric current is connected, the tungsten is heated to 2,000 to 3,300 K (1,730 to 3,030 °C; 3,140 to 5,480 °F) and glows, emitting light that approximates

2464-599: The inside of the tube, and other details of the lamp and its auxiliaries before the new device was ready for the public." The first practical LED arrived in 1962. In the United States , incandescent light bulbs including halogen bulbs stopped being sold as of August 1, 2023, because they do not meet minimum lumens per watt performance metrics established by the U.S. Department of Energy . Compact fluorescent bulbs are also banned despite their lumens per watt performance because of their toxic mercury that can be released into

2520-429: The lamp's life. Some lasers have been adapted as an alternative to LEDs to provide highly focused illumination. Carbon arc lamps consist of two carbon rod electrodes in open air, supplied by a current-limiting ballast . The electric arc is struck by touching the rod tips then separating them. The ensuing arc produces a white-hot plasma between the rod tips. These lamps have higher efficacy than filament lamps, but

2576-406: The luminaire. Those designed for 12- or 24-volt operation have compact filaments, useful for good optical control. Also, they have higher efficacies (lumens per watt) and longer lives than non-halogen types. The light output remains almost constant throughout their life. Fluorescent lamps consist of a glass tube that contains mercury vapour or argon under low pressure. Electricity flowing through

2632-531: The negative (−) terminal, work is done by the charges on the device. The potential energy of the charges due to the voltage between the terminals is converted to kinetic energy in the device. These devices are called passive components or loads ; they 'consume' electric power from the circuit, converting it to other forms of energy such as mechanical work , heat, light, etc. Examples are electrical appliances , such as light bulbs , electric motors , and electric heaters . In alternating current (AC) circuits

2688-410: The number of hours of operation at which 50% of them fail, that is the median life of the lamps. Production tolerances as low as 1% can create a variance of 25% in lamp life, so in general some lamps will fail well before the rated life expectancy, and some will last much longer. For LEDs, lamp life is defined as the operation time at which 50% of lamps have experienced a 70% decrease in light output. In

2744-771: The quantities as vectors. Real power is represented as a horizontal vector and reactive power is represented as a vertical vector. The apparent power vector is the hypotenuse of a right triangle formed by connecting the real and reactive power vectors. This representation is often called the power triangle . Using the Pythagorean Theorem , the relationship among real, reactive and apparent power is: (apparent power) 2 = (real power) 2 + (reactive power) 2 {\displaystyle {\text{(apparent power)}}^{2}={\text{(real power)}}^{2}+{\text{(reactive power)}}^{2}} Real and reactive powers can also be calculated directly from

2800-520: The simple equation P = IV may be replaced by a more complex calculation. The closed surface integral of the cross-product of the electric field intensity and magnetic field intensity vectors gives the total instantaneous power (in watts) out of the volume: ℘ = ∮ area ( E × H ) ⋅ d A . {\displaystyle \wp =\oint _{\text{area}}(\mathbf {E} \times \mathbf {H} )\cdot d\mathbf {A} .} The result

2856-540: The size of rooms that provide standby power for telephone exchanges and computer data centers . The electric power industry provides the production and delivery of power, in sufficient quantities to areas that need electricity , through a grid connection . The grid distributes electrical energy to customers. Electric power is generated by central power stations or by distributed generation . The electric power industry has gradually been trending towards deregulation – with emerging players offering consumers competition to

SECTION 50

#1732858473659

2912-644: The technically improved Daniell cell in 1836, batteries have become a common power source for many household and industrial applications. According to a 2005 estimate, the worldwide battery industry generates US$ 48 billion in sales each year, with 6% annual growth. There are two types of batteries: primary batteries (disposable batteries), which are designed to be used once and discarded, and secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times. Batteries are available in many sizes; from miniature button cells used to power hearing aids and wristwatches to battery banks

2968-422: The traditional public utility companies. Electric power, produced from central generating stations and distributed over an electrical transmission grid, is widely used in industrial, commercial, and consumer applications. A country's per capita electric power consumption correlates with its industrial development. Electric motors power manufacturing machinery and propel subways and railway trains. Electric lighting

3024-419: The tube causes the gases to give off ultraviolet energy. The inside of the tubes are coated with phosphors that give off visible light when struck by ultraviolet photons . They have much higher efficiency than incandescent lamps. For the same amount of light generated, they typically use around one-quarter to one-third the power of an incandescent. The typical luminous efficacy of fluorescent lighting systems

3080-582: The voltage wave and the RMS value of the current wave is known as apparent power . The real power P in watts consumed by a device is given by ℘ = 1 2 V p I p cos ⁡ θ = V r m s I r m s cos ⁡ θ {\displaystyle \wp ={1 \over 2}V_{p}I_{p}\cos \theta =V_{\rm {rms}}I_{\rm {rms}}\cos \theta } where The relationship between real power, reactive power and apparent power can be expressed by representing

3136-491: Was based on the concept that the high melting point of platinum would allow it to operate at high temperatures and that the evacuated chamber would contain fewer gas molecules to react with the platinum, improving its longevity. Although it was an efficient design, the cost of the platinum made it impractical for commercial use. William Greener , an English inventor, made significant contributions to early electric lighting with his lamp in 1846 (patent specification 11076), laying

#658341