Electricity. Is the set of physical phenomena. Associated with, the presence, and motion of matter that has a property, of electric, charge in, early. Days electricity. Was considered, as being not related, to magnetism. Later. On many, experimental. Results, and the development, of Maxwell's, equations, indicated. That both electricity, and magnetism, are from a single phenomenon. Electromagnetism. Various. Common, phenomena, are related to electricity, including. Lightning static. Electricity, electric. Heating electric, discharges, and many others. The. Presence, of an electric charge, which can be either positive or, negative produces. An electric, field the. Movement, of electric, charges, as an electric, current and produces, a magnetic field. When a charge is placed in a location with, a nonzero electric. Field a force will act on it the. Magnitude, of this force is, given by Coulomb's law thus. If that charge were to move the electric, field would be doing work on the electric, charge, thus. We can speak of electric, potential, at a certain, point in space which is equal to the work done by an external agent, in carrying, a unit of positive, charge from an arbitrarily, chosen reference. Point to that point without any acceleration. And as typically, measured in volts. Electricity. Is at the heart of many modern technologies. Being used for. Electric. Power where, electric, current is used to energize equipment. Electronics. Which, deals with electrical. Circuits, that involve active electrical. Components. Such as vacuum, tubes transistors, diodes. And, integrated circuits. And associated. Passive, interconnection technologies. Electrical. Phenomena, have been studied, since antiquity though progress in theoretical, understanding. Remains, slow until the 17th, and 18th centuries. Even. Then practical, applications. For electricity, were few and it would not be until the late 19th, century that, electrical, engineers, were able to put it to industrial, and residential, use, the. Rapid expansion in, electrical, technology at, this time transformed. Industry, and society becoming. A driving, force for the Second Industrial Revolution. Electricity's. Extraordinary. Versatility. Means it can be put to an almost limitless set, of applications. Which include, transport. Heating, lighting. Communications. And computation. Electrical. Power is now the backbone, of modern, industrial, society. Topic. History. Long, before any knowledge of electricity, existed. People were aware of shocks from electric, fish. Ancient. Egyptian, texts, dating from 20 750. BCE, referred, to these fish as the Thunderer. Of the nile and described. Them as the protectors. Of all. Other fish electric. Fish were again reported, millennia, later by, ancient Greek Roman, and Arabic natural, ists and physicians.
Several. Ancient writers, such, as Pliny, the Elder, and scribe O'Neill Argost, attested, to the numbing effect of electric, shocks delivered by electric, catfish, and electric, rays and knew that such shocks could travel along conducting, objects. Patients. Suffering from ailments, such as gout or headache were directed, to touch electric, fish in the hope that the powerful jolt might cure them, possibly. The earliest and, nearest approach to the discovery, of the identity, of lightning, and electricity from any other source, is to be attributed, to the Arabs who before the 15th, century had, the Arabic, word for lightning, rod rode applied, to the electric, ray ancient, cultures around the Mediterranean. Knew that certain objects, such as rods, of amber could be rubbed with cat's fur to attract light objects, like feathers. Dailies. Of Miletus made a series, of observations on, static, electricity around, 600. BC from. Which he believed that friction, rendered amber magnetic, in contrast. To minerals, such as magnetite. Which needed, no rubbing. Daley's. Was incorrect, in believing the attraction. Was due to a magnetic effect, but later science, would prove a link between magnetism. And electricity. According. To a controversial. Theory, the Parthians may have had knowledge of electroplating, based, on the 1936. Discovery, of the Baghdad battery which. Resembles, a galvanic cell though, it is uncertain whether the artifact, was electrical, in nature. Electricity. Would remain little more than an intellectual, curiosity, for. Millennia until 1600. When the English scientist, William Gilbert, wrote de magnet, in which he made a careful, study of electricity and. Magnet, distinguishing. The lodestone, effect, from static, electricity produced. By rubbing amber, he. Coined the new Latin word electric, Asst of amber. Or, like. Amber, from. Electron-electron, the. Greek word for Amber to, refer. To the property, of attracting, small objects. After being, rubbed, this. Association, gave, rise to the, English words, electric. And. Electricity. Which. Made their first appearance in print in Thomas, Brown's sueded, Ixia epidemic, ax of 16 46 further. Work was conducted in the 17th, and early 18th centuries. By otto von Gierke. Robert Boyle Stephen, gray and C F du Fay, later. In the 18th century Benjamin. Franklin, conducted, extensive research, in electricity, selling. His possessions, to fund his work in. June. 1750. - he is reputed to have attached, a metal key to the bottom of a dampened, kite string and flown the kite in a storm threatened. Sky a succession. Of sparks, jumping, from the key to the back of his hand showed, that lightning, was indeed electrical, in nature, he. Also explained. The apparently, paradoxical. Behavior, of the Leyden jar as a device, for storing large amounts of electrical, charge in terms of electricity, consisting. Of both positive, and negative charges in. 1791. Luigi. Galvani published. His discovery of, bio electromagnetics. Demonstrating. That electricity. Was the medium, by which neurons passed, signals, to the muscles. Alessandro. Voltas, battery or voltaic, pile of 1800. Made from alternating, layers of zinc and copper provided. Scientists. With a more reliable source of electrical, energy than, the electrostatic. Machines, previously. Used the, recognition. Of electromagnetism. The unity, of electric, and magnetic phenomena. Is due to Hans Christian, ørsted and. Andre Murray on pair in 1819. To 1820. Michael. Faraday, invented, the electric motor, in 1821. And Georg, ohm mathematically. And the, electrical, circuit, in 1827. Electricity. And magnetism, and light were, definitively, linked, by James Clerk Maxwell in, particular. In his unphysical, lines, of force in. 1861. And 1862. While the early 19th, century had, seen rapid, progress in electrical, science the late 19th, century would, see the greatest progress in electrical, engineering. Through. Such people as Alexander. Graham Bell Otto blabby Thomas. Edison, galileo, ferraris Oliver. Heaviside ano. Sedlec, william, thomson 1st, Baron, Kelvin Charles. Algernon, Parsons, Werner, von Siemens Joseph. Swan Reginald. Fessenden Nikola. Tesla and George, Westinghouse. Electricity. Turned from a scientific, curiosity, into. An essential, tool for modern, life, in. 1887. Heinrich, hertz discovered. That electrodes, illuminated. With ultraviolet, light create, electric, sparks, more easily, in. 1905. Albert Einstein. Published, a paper that explained, experimental.
Data From, the photoelectric. Effect as, being the result of light energy being, carried, in discrete, quantized, packets, energizing. Electrons. This. Discovery, led to the quantum, revolution, Einstein. Was awarded, the Nobel Prize in Physics in 1921, for. His discovery, of the law of the photoelectric effect. The. Photoelectric. Effect is, also employed in photo, cells such as can be found in solar panels and this is frequently, used to, make electricity, commercially. The. First solid-state. Device, was the cat's whisker, detector, first. Used in the 1900s. In radio receivers. A whisker. Like wire is placed lightly, in contact, with a solid crystal, such as a germanium, crystal. To detect a radio signal by the contact, junction effect in. A solid-state. Component, the current is confined, to solid elements, and compounds engineered. Specifically. To switch and amplify, it, current. Flow can be under stood in two forms, as, negatively-charged. Electrons and. As positively. Charged, electron, deficiencies. Called holes, these. Charges, and holes are understood, in terms of quantum, physics the, building, material, is most often a crystalline, semiconductor the. Solid-state device, came into its own with the invention of the transistor in. 1947. Common. Solid-state. Devices, include. Transistors. Microprocessor. Chips and RAM a, specialized. Type of ram called, flash ram is used in USB, flash drives, and more recently, solid-state. Drives to replace mechanically. Rotating, magnetic disk hard disk drives. Solid-state. Devices. Became, prevalent in the 1950s. And the 1960s, during. The transition, from vacuum, tubes to semiconductor. Diodes, transistors. Integrated. Circuit, IC and, the light emitting diode, led. Topic. Concepts. Topic. Electric. Charge. The, presence, of charge gives, rise to an, electrostatic, force. Charges, exert, a force on each other an effect, that was known though not understood, in antiquity. A, lightweight. Ball suspended from a string can, be charged by touching it with a glass rod that has itself been charged, by rubbing, with a cloth if a, similar ball is charged, by the same glass rod it is found to repel the first the charge acts to force the two balls apart, two. Balls that are charged with a rubbed amber rod also, repel each other, however. If one ball as charged, by the glass rod and the other by an amber rod the two balls are found to attract each other, these. Phenomena. Were investigated. In the late 18th, century by charles-augustin. De, Coulomb who deduced that charge manifests. Itself in two opposing, forms, this. Discovery, led to the well-known axiom. Like charged, objects, repel and opposite, charged, objects, attract, the force acts on the charged particles, themselves hence, charge has a tendency. To spread itself as evenly as possible over. A conducting, surface, the. Magnitude, of the electromagnetic. Force whether, attractive. Or repulsive is, given, by Coulomb's law which, relates the force to the product of the charges and has an inverse-square relation. To the distance between them, the. Electromagnetic. Force is very strong second. Only in strength, to the strong interaction. But unlike that force it operates, over all distances, in. Comparison. With the much weaker gravitational. Force, the electromagnetic, force. Pushing, two electrons, apart, as 1042. Times that of the gravitational. Attraction pulling. Them together study. Has shown that the origin, of charges, from certain, types of subatomic particles. Which have the property of electric, charge. Electric. Charge gives rise to and interacts, with the electromagnetic. Force one of the four fundamental, forces of nature, the. Most familiar carriers. Of electrical, charge are the electron, and proton. Experiment. Has shown charge to be a conserved, quantity that, is the net charge, within an electrically, isolated, system, will always remain constant regardless, of any changes, taking place within, that system, within. The system, charge, may be transferred. Between bodies, either by direct, contact or, by passing along, a conducting.
Material Such as a wire, the. Informal, term static, electricity, refers. To the net presence, or imbalance. Of charge, on a body usually. Caused when dissimilar. Materials, are rubbed together transferring. Charge from one to the other, the. Charge on electrons, and protons as, opposite, in sign hence, an amount of charge may be expressed, as being either negative, or positive, by. Convention, the charge carried, by electrons as. Deemed negative, and that by protons, positive a custom, that originated, with the work of Benjamin, Franklin, the. Amount of charge is usually, given the symbol Q and expressed, in coulombs, each electron, carries, the same charge of approximately. Minus one point six zero to two times 10 minus 19, coulomb, the. Proton, has a charge, that is equal and opposite, and thus plus one point six zero to two times 10 minus 19, Coulomb. Charges. Possessed, not just by matter but also by, antimatter each antiparticle. Bearing an equal and opposite, charge to its corresponding, particle charge, can be measured, by a number of means an early instrument. Being the goldleaf electroscope. Which, although still in use for classroom, demonstrations. Has been superseded, by the electronic. Electrometer. Topic. Electric. Current. The, movement, of electric, charge is known as an electric, current the intensity, of which is usually, measured in amperes, current, can. Consist, of any moving charged particles most commonly, these are electrons, but any charge in motion, constitutes. A current. Electric. Current can flow through some, things, electrical, conductors, but will not flow through an electrical, insulator by, historical, convention. A positive, current is defined as having the same direction of flow as any positive, charge it contains, or to flow from the most positive part, of a circuit, to the most negative part. Current. Ii find in this manner is called conventional, current, the, motion, of negatively, charged, electrons, around an electric, circuit one of the most familiar forms. Of current is the steamed positive, in the opposite, direction to, that of the electrons. However. Depending. On the conditions, an electric, current can consist, of a flow of charged, particles in, either direction or even in both directions, at, once, the. Positive, to negative convention. Is widely used to, simplify this situation. The. Process, by which electric.
Current Passes, through a material, as termed electrical. Conduction, and its nature varies, with that of the charged particles and, the material, through which they are traveling. Examples. Of electric, currents, include, metallic, conduction, where electrons, flow, through a conductor, such as metal an electrolysis. Where, ions charged. Atoms, flow through liquids, or through plasmas, such as electrical, sparks, while. The particles, themselves can, move quite slowly sometimes, with an average drift, velocity. Only fractions. Of a millimeter, per second, the electric, field that drives them itself, propagates. At close to the speed of light enabling, electrical. Signals, to pass rapidly, along wires current. Causes several observable. Effects, which historically, were the means of recognizing. Its presence. That. Water could be decomposed by, the current, from a voltaic pile, was discovered, by Nicholson, and Carlisle, in 1800. A process, now known as electrolysis. Their, work was greatly expanded upon, by Michael, Faraday in 1833. Current. Through a resistance, causes, localized. Heating and effect James, Prescott, Joule studied. Mathematically. In 1840. One. Of the most important, discoveries relating. To current, was made accidentally. By Hans Christian, ørsted in. 1820. When while, preparing, a lecture he witnessed the current in a wire disturbing. The needle of a magnetic, compass, he. Had discovered, electromagnetism. A fundamental. Interaction. Between electricity. And magnetics. The. Level of electromagnetic. Emissions generated. By electric, arcing is high enough to produce, electromagnetic. Interference. Which can be detrimental to, the workings, of adjacent, equipment, in engineering. Or household, applications. Current, is often described, as being either, direct, current, DC or, alternating. Current, AC. These. Terms refer to how the current, varies in time direct. Current is produced by example, from a battery and required, by most electronic. Devices is a unidirectional. Flow from the positive part of a circuit, to the negative, if as. Is most common, this flow is carried, by electrons they.
Will Be traveling, in the opposite, direction. Alternating. Current is any current, that reverses, direction, repeatedly, almost, always this takes the form of a sine wave. Alternating. Current thus, pulses, back and forth within a conductor, without the charge moving any net distance over time, the. Time averaged, value, of an alternating, current is, zero but it delivers energy, in first one direction, and then the reverse. Alternating. Current is affected, by electrical, properties, that are not observed, under steady state direct. Current such as inductance, and capacitance. These. Properties, however can, become important, when circuitry. Is subjected, to transients. Such as when first energized. Topic. Electric. Field. The, concept, of the electric, field was introduced, by Michael Faraday an electric. Field as created, by a charged, body in the space that surrounds it, and results, in a force exerted on any other charges, placed, within the field the. Electric, field acts between two charges, in a similar, manner to the way that the gravitational. Field acts between, two masses, and like it extends, towards, infinity, and shows an inverse-square relationship. With distance. However. There, is an important, difference, gravity. Always acts, in attraction, drawing two masses, together while, the electric, field can result in either attraction. Or repulsion. Since. Large bodies, such as planets, generally, carry no net charge the electric, field at a distance as, usually, zero thus. Gravity, as the dominant, force at distance, in the universe, despite, being much, weaker, an. Electric. Field generally. Varies, in space and its strength at any one point as defined, as the force per unit charge that, would be felt by a stationary. Negligible. Charge if placed at that point the. Conceptual. Charge termed, a test charge must be vanishingly, small to, prevent its own electric, field disturbing. The main field and must also be stationary, to prevent the effect of magnetic fields. As the. Electric, field is defined in terms of force and force, as a vector so it follows that an electric, field is also a vector having both magnitude, and direction. Specifically. It is a vector field the study of electric, fields, created, by stationary. Charges, as called electrostatics. The. Field may be visualized. By a set of imaginary. Lines whose direction, at any point as the same as that of the field this. Concept, was introduced, by faraday whose term lines of force still, sometimes sees, use, the. Field lines are the paths that a point positive, charge would seek to make as it was forced to move within the field they are however an imaginary, concept with, no physical existence, and the field permeates, all the intervening, space between, the lines. Field. Lines emanating from, stationary, charges, have several, key properties, first that they originate, at positive, charges and terminate, at negative, charges, second. That they must enter any good conductor, at right angles, and third that they may never cross, nor close in on themselves a hollow conducting. Body carries, all its charge on its outer surface. The. Field is therefore, zero at, all places inside, the body this. Is the operating, principle, of the Faraday, cage a conducting, metal shell which isolates, its interior from outside, electrical, effects. The. Principles, of electrostatics. Are important, when designing items. Of high voltage equipment. There. Is a finite, limit to the electric, field strength that may be withstood by any medium. Beyond. This point electrical. Breakdown occurs. And an electric, arc causes, flashover, between, the charged parts, air. For, example, tends to arc across small gaps at electric, field strengths, which exceed, 30 kilo, volts, per centimeter over. Larger. Gaps its breakdown strength, is weaker, perhaps, one kilo, volt per centimeter, the. Most visible, natural, occurrence, of this as lightning, caused when charge becomes, separated in, the clouds by rising columns, of air and raises, the electric, field in the air to greater than it can withstand, the. Voltage, of a large lightning, cloud may be as high as 100. Mega volts, and have discharge, energies, as great as 250. Kilo watt hours the field strength is greatly affected, by nearby conducting. Objects, and it is particularly, intense, when it is forced to curve around sharply. Pointed objects. This. Principle, as exploited, in the Lightning conductor, the sharp spike of which acts to encourage, the lightning stroke to develop there rather than to the building it serves to protect.
Topic. Electric. Potential. The, concept, of electric, potential is closely linked, to that of the electric field a small. Charge, placed, within an electric, field experiences. Of force and to have brought that charge to that point against, the force requires, work, the. Electric, potential, at any point as defined, as the energy required to bring a unit test charge from an infinite, distance slowly, to that point it. Is usually, measured in volts and 1 volt as the potential for which one Joule of work must, be expended, to bring a charge of one Coulomb, from infinity, this. Definition, of potential, while formal, has little practical application. And a more useful concept, is that of electric, potential, difference and, as the energy, required to move a unit charge, between two, specified, points, an, electric. Field has the special property that, it is conservative, which, means that the path taken, by the test charge is irrelevant all paths between two, specified, points, expend, the same energy and the say unique value, for potential. Difference, may be stated, the. Volt is so strongly, identified. As the unit of choice for measurement, and description, of electric, potential difference that the term voltage, sees greater everyday, usage. For. Practical, purposes, it is useful, to define a common, reference point to which potentials. May be expressed, and compared, while. This could be at infinity, a much more useful reference. As the earth itself, which is assumed to be at the same potential, everywhere. This. Reference point naturally. Takes the name earth or ground earth. Is assumed to be an infinite source of equal amounts, of positive and negative charge and is therefore electrically. Uncharged, a nun. Chargeable, electric, potential, as a scalar, quantity that, is it has only magnitude, and not Direction it. May be viewed, as analogous, to height just as a released, object, will fall through a difference, in Heights caused by a gravitational. Field so a charge will fall across the voltage caused by an electric, field as relief. Maps show, contour, lines marking, points of equal height a set of lines marking, point of equal potential, known, as equipotentials. Maybe drawn around an electro statically charged, object, the. Equipotentials. Cross, all lines of force at right angles, they, must also lie parallel, to a conductors, surface, otherwise, this would produce a force that will move the charge carriers, to even the potential of the surface. The. Electric, field was formally, defined, as the force exerted per unit charge but the concept, of potential, allows for a more useful and equivalent, definition. The electric, field as the local gradient, of the electric potential. Usually. Expressed, in volts per, meter the vector direction, of the field as the line of greatest slope, of potential, and where the equipotentials. Like, closest, together. You. Topic. Electromagnets. For Steve's discovery, in 1821. That, a magnetic, field existed. Around all sides of a wire carrying, an electric current indicated. That there was a direct, relationship, between electricity. And magnetism. Moreover. The interaction. Seemed different from gravitational, and, electrostatic. Forces the two forces of nature then, known the. Force on the compass, needle did, not direct, it tore away from, the current-carrying wire but, acted at right angles, to it force. Did slightly, obscure, words were that the electric, conflict, acts in a revolving, manner the. Force also depended, on the direction of the current / if the flow was reversed, then the force did - or stood did not fully understand. His discovery, but he observed, the effect was reciprocal. A current, exerts a force on a magnet, and a magnetic field exerts, a force on a current, the. Phenomenon, was further investigated. By ampere, who discovered, that two parallel, current-carrying, wires. Exerted. A force upon. Each other two wires conducting. Currents, in the same direction are, attracted, to each other while, wires containing. Currents, in opposite, directions are, forced apart the. Interaction. Is mediated, by the magnetic, field, each current, produces, and forms the basis, for the International. Definition, of the ampere. This. Relationship. Between magnetic. Fields, and currents, is extremely, important, for it led to Michael Faraday's, invention. Of the electric motor in, 1821. Faraday's. Homopolar, motor consisted. Of a permanent magnet sitting, in a pool of mercury a. Current. Was allowed through a wire suspended, from, a pivot above, the magnet, and dipped into the mercury, the. Magnet, exerted, a tangential, force on the wire making, its circle around the magnet for as long as the current was maintained.
Experimentation. By Faraday, in 1831. Revealed. That a wire moving, perpendicular, to a magnetic, field developed. A potential, difference between its ends, further. Analysis. Of this process, known, as electromagnetic. Induction enabled. Him to the principle, now known as Faraday's, law of induction that, the potential difference induced. In a closed circuit, is proportional. To the rate of change of magnetic flux, through the loop. Exploitation. Of this discovery, enabled, him to invent, the first electrical. Generator, in 1831. In which he converted the mechanical. Energy of a rotating copper, disc to electrical, energy. Faraday's. Disk was inefficient, and of no use as a practical, generator, but it showed the possibility of generating. Electric, power using, magnetism, a possibility. That would be taken up by those that followed on from his work. Topic. Electrochemistry. The, ability, of chemical, reactions, to produce electricity, and conversely, the ability, of electricity, to drive chemical. Reactions, has a wide array of uses. Electrochemistry. Has always been, an important, part of electricity, from. The initial invention, of the voltaic pile. Electrochemical. Cells have evolved, into the many different, types of batteries, electroplating. And electrolysis. Cells. Aluminium. Is produced, in vast quantities this, way and many portable, devices are electrically, powered using rechargeable cells. You. Topic. Electric. Circuits. An electric. Circuit is an interconnection, of electric, components. Such that electric, charge is made to flow along a closed, path a circuit, usually, to perform, some useful, task, the. Components. In an electric, circuit can take many forms which, can include elements, such as resistors, capacitors. Switches. Transformers. And electronics. Electronic. Circuits, contain, active components. Usually. Semiconductors. And typically, exhibit nonlinear. Behavior requiring. Complex. Analysis. The. Simplest, electric, components, are those that are termed passive, and linear while they may temporarily, store, energy they contain, no sources, of it and exhibit, linear responses. To stimuli the resistor, is perhaps the, simplest of passive, circuit, elements, as its name suggests it, resists, the current, through it dissipating. Its energy, as heat the. Resistance, is a consequence. Of the motion, of charge through a conductor, in metals, for example resistance. Is primarily, due to collisions, between electrons and. Ions, Ohm's. Law is, a basic, law of circuit, theory stating, that the current passing, through a resistance, is directly proportional. To the potential difference across it, the. Resistance of most materials. Is relatively, constant over a range of temperatures, and currents, materials. Under these conditions. Are known as ohmic, the. Ohm the, unit of resistance was. Named in honor of Georg, ohm and is symbolized, by the Greek letter Omega, one. Ohm is the resistance, that will produce a potential, difference of one volt in response, to a current, of 1 amp the capacitor, is a development. Of the Leyden jar and as a device, that can store charge and thereby storing, electrical, energy, in the resulting, field it. Consists. Of two conducting, plates separated, by, a thin insulating. Dielectric. Layer in practice. Thin metal foils, are coiled, together increasing.
The Surface area per unit volume and, therefore the capacitance. The. Unit of capacitance. Is the ferret named after Michael Faraday, and given the symbol F one farad is the Kapow students that develops, a potential, difference of one volt when, it stores a charge of one Coulomb, a, capacitor. Connected to a voltage supply initially. Causes, a current, as it accumulates charge, this current will however decay, in time as the capacitor, fills eventually. Falling to zero a, capacitor. Will therefore not, permit a steady state current but instead blocks it the inductor, as a conductor, usually. A coil, of wire that, stores energy in a magnetic field in response, to the current through it when. The current changes, the magnetic field is - inducing. A voltage, between the ends of the conductor, the. Induced voltage is, proportional to the time rate of change of the current the. Constant, of proportionality has. Termed the inductance, the, unit of inductance is, the Henry named, after Joseph, Henry, a contemporary. Of Faraday. 1. Henry is the inductance, that will induce a potential, difference of one volt if, the current through it changes, at a rate of 1 ampere, per second, the. Inductors, behavior, as in some regards, converse, to that of the capacitor, it will freely allow, an unchanging. Current but opposes, a rapidly, changing one. Topic. Electric. Power. Electric. Power is the rate at which electric. Energy is transferred, by an electric, circuit, the. SI unit of power as the watt one Joule per second. Electric. Power like, mechanical. Power 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 as, P. Equals. Work done per unit time. Equals. Q. V. Tea. Equals. I. V. Displaced. ILP, equals, text, work done per unit, time equals, frac. QV. T equals, IV. Where. Q. Is electric, charge in coulombs. T. Is time in seconds, i is. Electric, current in amperes. Vias, electric, potential, or voltage in, volts electricity. Generation, is often done with electric. Generators, but can also be supplied by chemical, sources, such as electric, batteries, are by other means from a wide variety of sources, of energy. Electric. Power is generally, supplied, to businesses, and homes by the electric, power industry. Electricity. Is usually, sold by the kilowatt, hour, 3.6, mega joules which is the product of power in kilowatts multiplied. By running time in hours. Electric. Utilities, measure power using, electricity. Meters which keep a running total, of the electric, energy delivered. To a customer. Unlike. Fossil fuels, electricity. Is a low entropy form, of energy and can be converted into motion or many other forms, of energy with high efficiency. You. Topic. Electronics. Electronics. Deals with electrical, circuits, that involve active electrical. Components. Such as vacuum, tubes transistors, diodes. Optoelectronics. Sensors. And integrated, circuits, and associated. Passive, interconnection technologies. The. Nonlinear, behavior of, active components. And their ability, to control, electron, flows makes, amplification. Of weak signals, possible, and electronics. Is widely used in, information, processing. Telecommunications. And signal, processing. The. Ability, of electronic. Devices to act as switches makes digital information, processing. Possible. Interconnection. Technologies such. As circuit, boards electronics. Packaging, technology. And other varied, forms of communication. Infrastructure, complete. Circuit, functionality. And transform. The mixed components. Into a regular, working system. Today. Most, electronic. Devices use, semiconductor. Components to, perform electron. Control, the. Study of semiconductor. Devices and. Related, technology. Is considered, a branch of solid-state, physics. Whereas the design and construction of, electronic. Circuits, to solve practical problems come. Under Electronics. Engineering. You. Topic. Electromagnetic. Wave. Faraday's. And amperes, work showed that a time-varying magnetic, field. Acted, as a source of an electric, field and a time varying, electric field, was a source of a magnetic field, thus. When either field, is changing in time then, a field of the other is necessarily, induced. Such. A phenomenon. Has the properties, of a wave and is naturally, referred, to as an electromagnetic. Wave. Electromagnetic. Waves were analysed theoretically. By James Clerk Maxwell in. 1864. Maxwell. Developed, a set of equations, that could unambiguously.
Describe, The interrelationship. Between electric. Field magnetic, field, electric, charge and electric, current, he. Could moreover, prove that such a wave would necessarily travel. At the speed of light and thus light itself, was a form of electromagnetic. Radiation. Maxwell's. Laws which. Unify, light fields. And charge are one of the great milestones. Of theoretical. Physics thus the work of many researchers, enabled. The use of electronics. To convert, signals into, high frequency. Oscillating, currents, and via suitably, shaped conductors. Electricity. Permits the transmission. And reception of, these signals, via radio waves, over, very long distances. Topic. Production. And uses. Topic. Generation. And transmission. In the, 6th century BC. The Greek philosopher. Thales of Miletus, experimented. With amber, rods and these experiments, were the first studies, into the production of electrical, energy, while. This method now known as the triboelectric effect, can, lift light objects, and generate, sparks it is extremely, inefficient, it. Was not until the invention of the voltaic pile. In the 18th, century that, a viable, source of electricity, became, available, the. Voltaic, pile, and it's modern descendant. The electrical, battery store. Energy chemically. And make it available on, demand in the form of electrical, energy, the. Battery is a versatile, and very common, power source, which is ideally, suited to many applications. But its energy storage, is finite, and once discharged. It must be disposed, of or recharged. For. Large electrical. Demands electrical. Energy, must be generated, and transmitted, continuously over. Conductive, transmission. Lines. Electrical. Power is usually generated by, electromechanical. Generators. Driven, by steam produced, from fossil fuel, combustion, or the heat released, from nuclear, reactions, or from other sources such as kinetic, energy, extracted, from wind or flowing water, the, modern. Steam turbine, invented, by Sir Charles Parsons, in, 1884. Today, generates, about 80 percent, of the electric, power in, the world using, a variety of heat sources. Such. Generators, bear, no resemblance to, Faraday's, homopolar, disc generator, of 1831. But, they still rely on his, electromagnetic. Principle, that a conductor, linking, a changing, magnetic field, induces a potential. Difference across its, ends the. Invention, in the late 19th, century of, the transformer. Meant that electrical, power could be transmitted. More efficiently, at a higher voltage but, lower current. Efficient. Electrical, transmission meant, in turn that electricity, could be generated, at centralized, power stations. Where it benefited, from economies, of scale, and then be dispatched, relatively.
Long Distances, to where it was needed. Since electrical. Energy, cannot, easily be stored, in quantities, large enough to meet demands on a national, scale at all times, exactly as, much must be produced, as is required, this. Requires, electricity, utilities. To make careful predictions. Of their electrical, loads and maintain, constant, coordination. With their power stations, a certain. Amount of generation, must, always be, held in reserve to cushion an electrical, grid against inevitable, disturbances. And losses. Demand. For electricity, grows, with great rapidity as, a nation, modernizes. And its economy, develops, the. United States showed a 12%, increase in demand during, each year of the first three decades of the 20th, century, a rate of growth that is now being experienced. By emerging. Economies, such as those of India or China. Historically. The growth rate for electricity, demand has outstripped, that for other forms, of energy environmental. Concerns, with electricity generation. Have, led to an increased, focus on generation. From renewable, sources in particular. From wind and hydro, power, while. Debate, can be expected, to continue over the environmental. Impact, of different means of electricity, production its final, form as relatively, clean. You. Topic. Applications. Electricity. Is a very convenient, way to transfer. Energy and, it has been adapted to a huge and growing number, of uses, the. Invention, of a practical, incandescent light, bulb in the 1870s. Led to lighting becoming, one of the first publicly, available, applications. Of electrical, power. Although. Electrification. Brought. With it its own dangers, replacing. The naked flames of gas lighting greatly, reduced fire hazards, within homes and factories. Public. Utilities, were set up in many cities targeting. The burgeoning market for electrical, lighting in the. Late 20th, century and, in modern times the trend has started to flow in the direction of deregulation. In the electrical, power sector, the resistive, Joule heating effect, employed. In filament, lightbulbs, also sees more direct, use in electric, heating, while. This is versatile, and controllable. It can be seen as wasteful, since most electrical, generation, has already, required, the production of heat at a power station a number. Of countries such, as Denmark have, issued legislation. Restricting, or, banning, the use of resistive. Electric, heating in new buildings. Electricity. Is however still a highly practical, energy, source for heating and refrigeration with. Air-conditioning heat, pumps representing. A growing sector for electricity, demand for heating and cooling the effects of which electricity. Utilities, are increasingly, obliged, to accommodate, electricity. Is used within telecommunications.
And Indeed, the electrical, Telegraph, demonstrated. Commercially. In, 1837. By Cooke, and Wheatstone was. One of its earliest applications. With. The construction, of first intercontinental. And then transatlantic. Telegraph. Systems in the 1860s. Electricity. Had enabled, communications. In minutes across the globe. Optical. Fiber and satellite, communication. Have taken, a share of the market for, communications, systems, but electricity, can be expected, to remain an essential, part of the process. The, effects of electromagnetism. Are most visibly, employed, in the electric, motor which provides, a clean and efficient, means of motivepower a. Stationary. Motor such, as a winch is easily, provided, with a supply, of power but, a motor that moves with its application. Such as an electric, vehicle is obliged, to either carry, along a power source, such as a battery or, to collect current, from a sliding, contact such, as a pantograph. Electrically. Powered vehicles. Are used in public transportation, such. As electric, buses and trains and an increasing, number of battery-powered, electric. Cars in private, ownership. Electronic. Devices make, use of the transistor. Perhaps, one of the most important, inventions of the 20th century, and a fundamental, building block, of all modern circuitry. A modern. Integrated, circuit, may contain, several billion, miniaturized. Transistors. In a region only a few centimetres, square. Topic. Electricity. And the natural, world. Topic. Physiological. Effects. A, voltage. Applied to a human, body causes, an electric current through the tissues, and although the relationship is, nonlinear, the greater the voltage the greater the current the. Threshold, for perception varies. With the supply, frequency and. With the path of the current but is about 0.1. Milli amperes, to 1 milli ampere, for mains frequency electricity. Though a current, as low as a micro, amp can be detected, as an electro, vibration, effect under certain conditions. If the. Current is sufficiently, high it will cause muscle contraction. Fibrillation. Of the heart and tissue burns, the. Lack of any visible, sign that a conductor, is electrified. Makes electricity, a particular. Hazard, the. Pain caused by an electric, shock can be intense, leading, electricity. At times to be employed, as a method, of torture, death. Caused by an electric, shock is referred, to as electrocution. Electrocution. Is still the means of judicial, execution. In some jurisdictions, though its use has become rarer, in recent, times. Topic. Electrical. Phenomena, in nature. Electricity. Is not a human, invention and may be observed, in several forms, in nature a prominent, manifestation. Of which is lightning, many. Interactions. Familiar, at the macroscopic level such. As touch friction. Or chemical, bonding are due to interactions. Between electric. Fields, on the atomic scale, the. Earth's magnetic, field is thought to arise from a natural, dynamo, of circulating. Currents, in the planets core, certain. Crystals, such as quartz, or even, sugar generate. A potential, difference across their, faces when subjected to external pressure, this. Phenomenon, is known as piezoelectricity, from, the Greek peas and peas and meaning, to press and was discovered, in 1880, by Pierre, and Jacques Curie, the.
Effect Is reciprocal. And when a piezoelectric. Material, is subjected, to an electric field a small change, in physical dimensions. Takes place section, bioelectric. Genesis in microbial, life as a prominent, phenomenon. In soils, and sediment, ecology, resulting, from anaerobic, respiration. The. Microbial, fuel cell mimics, this ubiquitous natural. Phenomenon. Some. Organisms. Such, as sharks, are able to detect and respond, to changes, in electric, fields, an ability known as electroreception. While others termed, electrogenic, are able to generate voltages. Themselves, to serve as a predatory, or defensive, weapon, the. Order Jim nota forms, of which the best-known example, as the electric, eel detect, or stun their prey via, high voltages, generated. From modified, muscle, cells called electrocytes. All. Animals. Transmit, information along. Their cell membranes, with voltage, pulses, called action, potentials, whose functions, include, communication, by, the nervous system, between neurons and muscles an, electric. Shock stimulates. This system, and causes, muscles, to contract. Action. Potentials, are also responsible, for coordinating. Activities in, certain, plants. Topic. Cultural. Perception. In, 1850. William, Gladstone asked. The scientist, Michael, Faraday why. Electricity. Was valuable. Faraday. Answered, one day sir, you may tax it in the 19th, and early 20th, century. Electricity. Was not part of the everyday life of many people even, in the industrialized. Western world, the. Popular, culture, of the time accordingly, often, depicted, it as a mysterious, quasi, magical, force that can slay the living revive, the dead or otherwise, bend, the laws of nature, this. Attitude, began with, the 1771. Experiments. Of Luigi, Galvani in which the legs of dead frogs were shown to twitch on application. Of animal electricity. Revitalization. Or. Resuscitation. Of apparently, dead or drowned persons, was reported, in the medical literature shortly. After Galvani's, work these. Results, were known to Mary Shelley when she authored Frankenstein. 1819. Although, she does not name the method of revitalization, of the monster, the. Revitalization. Of monsters, with electricity, later, became a stock, theme in horror films, as, the. Public familiarity. With electricity, as the lifeblood of the Second Industrial Revolution, grew.
Its Wielders, were more often cast in a positive, light such, as the workers who finger. Death at their gloves end as they peace and repeats, the living wires. In. Rudyard. Kipling's. 1907. Poems, sons of martha electrically. Powered vehicles. Of every sort featured, large in adventure, stories, such as those of Jules Verne and the Tom Swift books, the. Masters of electricity. Whether fictional. Or real, including. Scientists, such as Thomas Edison Charles. Steinmetz, or Nikola Tesla, were, popularly, conceived. Of as having wizard-like powers, with electricity, ceasing. To be a novelty, and becoming a necessity of everyday life in the later half of the 20th century. It required, particular. Attention, by popular, culture only, when it stops flowing an event that usually, signals, disaster. The. People, who keep it flowing such, as the nameless, hero of Jimmy Webb's song, Wichita. Lineman. 1968. Are still often cast as heroic, wizard-like figures. Topic. See also. Ampère's. Circuital law, connects. The direction, of an electric, current and its associated, magnetic, currents. Electric. Potential, energy the, potential energy of a system of charges. Electricity. Market the sale of electrical. Energy. Hydraulic. Analogy, an analogy. Between the flow of water and electric, current. Equals. Equals, notes.
2019-07-07