
:''Separate-but related articles are Electrical energy, and Electric power'' Electricity is a property of certain subatomic particles (e.g. electrons / protons) which couples to electromagnetic fields and causes attractive and repulsive forces between them. Electricity gives rise to one of the four fundamental forces of nature, and is a conserved property of matter that can be quantified. In this sense, the phrase "quantity of electricity" is used interchangeably with the phrases "electric charge" and "quantity of charge." There are two types of electricity or charge: we call one kind of electricity positive and the other negative. Through experimentation, we find that like-charged objects repel and opposite-charged objects attract one another. The magnitude of the force of attraction or repulsion is given by Coulomb's law. Some electrical effects are discussed under electrical phenomenon and electromagnetism. The SI unit of electricity is the coulomb, which has the abbreviation "C". The symbol ''Q'' is used in equations to represent the quantity of electricity or charge. For example, "''Q'' = 0.5 C" means "the quantity of electric charge is 0.5 coulomb." == History == According to Thales, writing ''circa'' 600 BCE, a form of electricity was known to the Ancient Greece, who found that rubbing fur on various substances, such as amber, would cause a particular attraction between the two. The Greeks noted that the amber buttons could attract light objects such as hair, and that if they rubbed the amber for long enough, they could even get a spark to jump. This is the origin of the word "electricity", from the Greek language ''ēlektron'' = "amber", which came from an old root (linguistics) ''ēlek-'' = "shine". An object found in Iraq in 1938, dated to about 250 BCE and called the Baghdad Battery, resembles an electrochemical cell and is believed by some to have been used for electroplating. There is no firm documentary evidence to indicate what the object was used for, though. There are other descriptions of supposedly electrical devices on Ancient Egypt walls, such as the Dendera light. Other devices discovered in Egyptian and other archaeological digs have been alleged to be battery (electricity). In 1600 the English scientist William Gilbert returned to the subject in ''De Magnete'', and coined the modern Latin word ''electricus'' from ''ηλεκτρον'' (''elektron''), the Greek word for "amber", which soon gave rise to the English words ''electric'' and ''electricity''. He was followed in 1660 by Otto von Guericke, who is regarded as having invented an early electrostatic generator. Other European pioneers were Robert Boyle, who in 1675 stated that electric attraction and repulsion can act across a vacuum; Stephen Gray, who in 1729 classified materials as conductors and insulators; and C. F. Du Fay, who first identified the two types of electricity that would later be called ''positive'' and ''negative''. The Leyden jar, a type of capacitor for electrical energy in large quantities, was invented at Leiden University by Pieter van Musschenbroek in 1745. William Watson (scientist), experimenting with the Leyden jar, discovered in 1747 that a discharge of static electricity was equivalent to an electric current. In June, 1752, Benjamin Franklin promoted his investigations of electricity and theories through the famous, though extremely dangerous, experiment of flying a Kite flying during a thunderstorm. Following these experiments he invented a lightning rod and established the link between lightning and electricity. If Franklin did fly a kite in a storm, he did not do it the way it is often described (as it would have been dramatic but fatal). It was either Franklin (more frequently) or Ebenezer Kinnersley of Philadelphia (less frequently) who created the convention of positive and negative electricity. As a result of this discovery, the Chinese word for "lightning" is now also used to mean "eletricity". Franklin's observations aided later scientists such as Michael Faraday, Luigi Galvani, Alessandro Volta, Andre Marie Ampere, and Georg Ohm whose work provided the basis for modern electrical technology. The work of Faraday, Volta, Ampere, and Ohm is honored by society, in that fundamental units of electrical measurement are named after them. Volta worked with chemicals and discovered that chemical reactions could be used to create positively charged anodes and negatively charged cathodes. When a conductor was attached between these, the voltage (also known as voltage) drives a current (electricity) between them through the conductor. The potential difference between two points is measured in units of volts in recognition of Volta's work. The late 19th and early 20th century produced such giants of electrical engineering as Nikola Tesla, inventor of the induction motor and the fundamental alternating current transmission system, Samuel Morse, inventor of the telegraph; Antonio Meucci, inventor of the telephone; Thomas Edison (inventor of the phonograph and a practical incandescent light bulb); George Westinghouse, inventor of the electric locomotive; Charles Steinmetz, theoretician of alternating current. Nikola Tesla performed experiments with very high voltages that are the stuff of legend, involving ball lightning and other effects (some have been duplicated or explained; and others which have not). Nikola Tesla, inventor of the induction motor and developer of polyphase systems, contributed to the world of electrodynamics the theory of polyphase alternating current, which he used to build the first induction motor, invented in 1882. In May 1885, Westinghouse, then president of the Westinghouse Electric Company in Pittsburgh, Pennsylvania, bought the rights to Tesla's patents for polyphase alternating-current dynamos. This led to a contest in the so-called court of public opinion as to which system would be adopted as the standard for power transmission (known as the War of Currents), Edison's direct-current system or Westinghouse's alternating-current method. Edison conducted a spirited public relations campaign which included his promotion of the electric chair as a method of execution (legal). The electric chair ran on Westinghouse's AC; Edison wanted to prove that AC power was capable of killing, and should therefore be viewed by the public as inherently dangerous. This FUD campaign included the electrocution of Topsy the Elephant. AC power was eventually adopted as the standard. == Electric power == Electric power is the popular name given to electrical energy production and distribution. For most consumers, electrical energy is generated centrally by utility companies using coal, natural gas, hydropower, nuclear power or petroleum. In 2000, U.S. electric utilities had 600 gigawatts of maximum summer generating capacity including 261 GW from coal, 118 GW from natural gas, 92 GW from hydropower, 86 GW from nuclear and 41 GW from petroleum. Little generating capacity is presently based on renewable energy sources such as solar power and wind power. Some individuals and communities prefer renewable sources because there is less pollution and because users of renewable energy sources can sometimes gain a measure of economic independence from the electrical utilities. Devices powered by electrical energy include lamps, computers and the Internet, radio and television, refrigeration, air conditioning, traffic signals, electric guitars and other electronic musics, and the spark plugs in automobiles. A summary of the applications of electric energy (written for non-specialists, and briefly explaining motors, transformers, transistors, digital, etc.) is the book, ''Industrial Electronics for Engineers, Chemists, and Technicians'', by D. J. Shanefield, William Andrew Publishing (Norwich, NY), 2001. In electrical engineering, the energy in electromagnetic fields is harnessed to perform useful work—either as a method to transmit energy to the appropriate place and then convert it back into a different, useful form of energy (for instance, heat, light, or motion), or by using the presence or level of electricity to convey information. Today's electrical engineers enjoy the ability to design circuits using pre-manufactured building blocks such as power supply, resistors, capacitors, semiconductors such as transistors, and integrated circuits. An integrated circuit inside a computer, the microprocessor, performs millions of computations per second. == Electric current == A flow of electricity is called an current (electricity). A direct current (DC) is a unidirectional flow; alternating current (AC) is a flow whose time average is zero, but is not zero at all times. That definition of AC implies that the flowing electricity repeatedly changes direction. (Polarity and numerical sign (i.e. negative vs. positive) are additional terms for direction in this sense). It is often important, particularly for safety reasons, that one side of a circuit be electrically bonded to an earth terminal. Such an earth terminal is usually connected to an electrode buried in the ground. The potential of earth (Ground (electricity) ) is defined as zero by convention, and the electrical conductivity between similarly buried electrodes is considered to be low enough that all earth terminals are effectively at the same voltage. The electricity which occurs naturally within Conductor (material)s can be forced to flow, while the charges within insulators are locked in place and cannot be moved. Some electrical devices that use electrical physics are called electronics. See electrical conduction for more information about charge flow in materials. Ohm's Law is an important relationship describing the behaviour of electric currents: : where is the applied voltage, measured in volts is the current, measured in amperes is the resistance, measured in ohms For historical reasons, electricity is said to flow from the most positive part of a circuit to the most negative part. The electric current thus defined is called ''conventional current''. It is now known that, depending on the type of conductor, 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. If another definition is used - for example, "electron current" - it should be explicitly stated. == Terminology issues == In addition to its definition by physicists, the word ''electricity'' has several popular definitions which are contradictory. Rather than using the word ''electricity'' to refer to the quantity of electric charge, many sources instead say that electricity is the quantity of electromagnetic energy measured in joules or kWh. Other sources call the motion of charges within a conductor by the name ''electricity'', and they measure the quantity of electricity in terms of amperes. Still others call a wide variety of electrical phenomena by the name ''electricity'', e.g. bioelectricity, piezoelectricity, triboelectricity, etc. It is advisable to be extremely careful when interpreting texts which employ the frequently misused term "electricity" in place of the more accurate terms electric charge, electric current, electrical energy, etc. == SI electricity units == == See also == * Main: electromagnetism, electrical phenomenon (electric charge), electric power (for energy transfer using electricity), electric shock, electric chair (execution) * Things: Battery (electricity), Lightning, Conductor * Engineering: Green electricity, Electrical wiring === Electrical phenomena in nature === * Lightning * Bioelectricity — Many animals are sensitive to electric fields, some (e.g., sharks) more than others (e.g., people). Most also generate their own electric fields, and a few, like the electric eel, deliberately generate strong fields to detect or stun their prey. * Neurons in the nervous system transmit information by electrical impulses known as action potentials. * Matter — since atoms and molecules are held together by electric forces. * The Earth's magnetic field — created by electric currents circulating in the planet's core. * Sometimes due to solar flares, a phenomenon known as a power surge can be created, which can be very damaging to sensitive electrical equipment such as computers. However, such damage can be prevented by using a surge protector. == External links == * [http://amasci.com/miscon/whatis.html What is electricity?] * [http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=electricity Merriam-Webster: Electricity] * [http://www.bibliomania.com/2/9/72/119/21387/1.html Tyndall: Faraday as Discovery: Identity of Electricities] * [http://www.eia.doe.gov/fuelelectric.html US Energy Department Statistics] * [http://www.mouthshut.com/readreview/38842-1.html How to save on your electricity bills] * [http://users.pandora.be/worldstandards/electricity.htm Electricity around the world] * [http://www.tufts.edu/as/wright_center/fellows/bob_morse_04/ A Comprehensive Collection of Franklin’s Electrical Works: The Electrical Writings of Benjamin Franklin], Created and Collected by Robert A. Morse (2004) Electricity bn:বিদ্যুত্ fa:برق hi:विद्युत
----- "there is a force between these charges that is directly proportional to the magnitude of the charge of the objects and inversely proportional to distance between them." Is that correct? Should it not rather be " ... and inversely proportional to ''the square of '' the distance between them."? The subsequent formula seems unnecessarily awkward. S. ---- Can anyone remember reading a short science fiction story about someone who is granted a wish, and decides that the best way to solve the world's problems is to abolish electricity? Unfortunately he doesn't know that electricity is what holds atoms together. His wish is granted, and the universe falls apart. If I knew the name of this story, I would add a reference to it in this article. - User:Heron *Perhaps, Electricity (Sci-fi) if it is long enough. ---- Hmm. I have to say this article is phenomenally America-centric. And pretty much glosses over everything before Ben Franklin, whose significance (on the other tentacle) to what followed, really is blown totally out of proportion. I mean, really! -- User:Cimon avaro 20:08, Sep 19, 2003 (UTC) == Removed from Current == Accuracy aside, the following 'graph does not belong in the section on Current. It may have some value elsewhere. :It is often important, particularly for safety reasons, that one side of a circuit be electrically bonded to an earth terminal. Such an earth terminal is usually connected to an electrode buried in the ground. The potential of earth (ground) is defined as zero by convention, and the electrical conductivity between similarly buried electrodes is considered to be low enough that all earth terminals are effectively at the same voltage. --User:Jerzy 01:35, 2003 Dec 12 (UTC) ==Main focus of this article ??== Many of the pointers to this page seems to mean ''electricity'' in the meaning ''electrical energy''. Perhaps there should be a separate article about electrical energy, with all relevant pointers so directed? -- User:Egil 07:46 Feb 7, 2003 (UTC) If I had started this article, I would have made it a disambiguation article with links to "electrical energy", "electrical power", "electric current", "electric charge" and all other electrical phenomena. The present article is about electric charge, so it could perhaps be merged with the article of that name. -- User:Heron I believe this article should focus on the commonest meaning of electricity, i.e. electric current. One proof of this is to look at the articles that link to here: most take the "electric current" view. It should start with a disambiguation paragraph linking to other electrical phenomena. User:Pcarbonn 19:21, 5 Sep 2004 (UTC) On the contrary, the commonest meaning of electricity is electrical energy. It is a widespread misconception that electric current is a form of energy. No, an Ampere is not a Joule. Just because many authors incorrectly give electric current the name "electricity" doesn't mean that reference works should support the error. In non-science topics, common usage *is* the correct usage, but in physics, a common misconception remains incorrect no matter how many people aquire that misconception. Physics books play by very different rules than dictionaries. ------- I agree that "Electricity" should become a disambiguation entry. In addition to articles on Electric Charge and Electrical Energy (etc.,) the present article can split off into an article about common misconceptions regarding the term Electricity. Because even the authors of many reference books have a fairly poor understanding of charge vs. energy, disambiguation becomes a proper topic for the science and education community, not just the usual Wikipedia issue. User:Wjbeaty 16:19 Dec 27, 2004 (PST) == How electricity kills == Electricity kills in either of these ways: * Current of at least 50 miliamps passing through the heart can cause it to stop. To get 50ma to the heart, there must be sufficent voltage to overcome the body's natural resistance. * The body's natural resistance can cause it to absorb the electricity and convert it to heat. Given enough power, this heat will cause the body to cook. For this, it does not matter if it is low voltage or low power, as long as the product of the two is high enough for the power to heat the body faster than it can dissipate the generated heat. As stated in the main article, Ohm's law gives the relationship between current, voltage, and resistance. When resitsance is present, both current and voltage must be non-zero for the other to exist. Power is the product of current and voltage. --User:Ssd 20:08, 13 Mar 2005 (UTC) I've tried to explain it to you, if you are not interested then too bad. Voltage DOES NOT EXIST in a physical manner, it is simply the difference of potential between two points. :That's silly. I can measure it, it exists. No, it isn't a physical substance. I can't see voltage. I can't see current. I can't see wind either, does it not exist either? Voltage, as you say, is the electrical potential between two points. If there is no potential, there will not be any current either. Neither current nor voltage alone are sufficent to describe electricity. Both must be considered. If voltage was not important, Ohm's law would also not be important. I suppose you could argue that given you have two independent variables and one dependent variable. However, which one you pick for the dependent variable is really just a matter of semantics or point of view. --User:Ssd 20:22, 13 Mar 2005 (UTC) You are misunderstanding what I am saying. When you pull out your voltmeter, you are not actually measuring voltage - you are measuring the DIFFERENCE in "pressure" between two points. In a wye connected system, for example, if your line voltage was 480v, your phase voltage would be 277v.(480/1.732, or the root of three). Now measure from phase to phase, and what would you have? exactly. --User:Vega007 By the way, no disrespect, but you CAN see current when it is arcing and sparking. Are you an electrician like myself or just an educated observer? ::When you see arcing, you are seeing voltage high enough to ionize the air and form a conductive path. If it is high current, the arc lasts longer and is thicker. If it is low current, you will see short lived thin arcs that will reoccur as the voltage becomes high enough for a new arc. (Technically, you don't see current or voltage, you see photons, but that's just being pedantic.) --User:Ssd 05:32, 16 Mar 2005 (UTC) :Voltage is a relative difference between two points. If you want to say that a single point has a voltage, then you have to choose a single reference point for the circuit, and you are implying a measurement relative to that point. That point is called ground. Although there are conventions for which point you call ground, you could technically define ''any'' point in the circuit as 0 V and measure all other points relative to it. - User:Omegatron 00:55, Mar 14, 2005 (UTC) I agree mostly with everything now here. A couple of fine points... Everything Omegatron said about voltage is exactly correct. However, when I think of voltage, I think of a power source. When I think of voltage from a power source, I think transmission line, which has (at least) two wires, and thus two points of reference from which to measure. If you grabbed those two with one hand, you'd be burned. If you grab one in each hand, there's a good chance voltage (and current) will pass through your body, and thus through your heart. For those purists that say "voltage does not exist, only current matters", I'd like to remind them that only ideal power sources can supply infinite voltage when met with high resistance, where a real power source won't get sufficent current through to matter if it can't supply the needed voltage. Likewise, the real power source when faced with zero resistance can't supply infinite current to keep voltage constant. Thus, all real power supplies have a maximum voltage and maximum current rating, and even if they are constant current (rare except battery chargers) or constant voltage (most are), when the maximum voltage or maximum current is surpassed, it will be unable to keep the other from sagging. This is why ''both'' ratings are important. It is thus incorrect to say only current or only voltage is important. This was my original point, more correctly stated. (These incremental changes from discussion like this I like to think make points clearer and help all parties see their errors and fuzzy thinking. Some of this probably should be integrated into a relevant article once it's all correct. --User:Ssd) ==Proposed focus== I was surprised to see how the focus of the article changes rapidly as you read into it. I'd suggest putting all the electric power discusions as links to those articles, and leaving "electricity" as more of a discussion of the fundamental physics. Static charge, dynamic charge, all the pith-ball-and-compass-needle history, etc. - and leave applications to other articles. --User:Wtshymanski 22:38, 16 May 2005 (UTC)
Electricity is a property of certain subatomic particles, such as electrons and protons, that gives rise to attractive and repulsive forces between them. It is one of the four fundamental forces of nature, and is a conserved property of matter that can be quantified. Electromagnetism
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Electricity
:''Separate-but related articles are Electrical energy, and Electric power'' Electricity is a property of certain subatomic particles (e.g. electrons / protons) which couples to electromagnetic fields and causes attractive and repulsive forces between them. Electricity gives rise to one of the four fundamental forces of nature, and is a conserved property of matter that can be quantified. In this sense, the phrase "quantity of electricity" is used interchangeably with the phrases "electric charge" and "quantity of charge." There are two types of electricity or charge: we call one kind of electricity positive and the other negative. Through experimentation, we find that like-charged objects repel and opposite-charged objects attract one another. The magnitude of the force of attraction or repulsion is given by Coulomb's law. Some electrical effects are discussed under electrical phenomenon and electromagnetism. The SI unit of electricity is the coulomb, which has the abbreviation "C". The symbol ''Q'' is used in equations to represent the quantity of electricity or charge. For example, "''Q'' = 0.5 C" means "the quantity of electric charge is 0.5 coulomb." == History == According to Thales, writing ''circa'' 600 BCE, a form of electricity was known to the Ancient Greece, who found that rubbing fur on various substances, such as amber, would cause a particular attraction between the two. The Greeks noted that the amber buttons could attract light objects such as hair, and that if they rubbed the amber for long enough, they could even get a spark to jump. This is the origin of the word "electricity", from the Greek language ''ēlektron'' = "amber", which came from an old root (linguistics) ''ēlek-'' = "shine". An object found in Iraq in 1938, dated to about 250 BCE and called the Baghdad Battery, resembles an electrochemical cell and is believed by some to have been used for electroplating. There is no firm documentary evidence to indicate what the object was used for, though. There are other descriptions of supposedly electrical devices on Ancient Egypt walls, such as the Dendera light. Other devices discovered in Egyptian and other archaeological digs have been alleged to be battery (electricity). In 1600 the English scientist William Gilbert returned to the subject in ''De Magnete'', and coined the modern Latin word ''electricus'' from ''ηλεκτρον'' (''elektron''), the Greek word for "amber", which soon gave rise to the English words ''electric'' and ''electricity''. He was followed in 1660 by Otto von Guericke, who is regarded as having invented an early electrostatic generator. Other European pioneers were Robert Boyle, who in 1675 stated that electric attraction and repulsion can act across a vacuum; Stephen Gray, who in 1729 classified materials as conductors and insulators; and C. F. Du Fay, who first identified the two types of electricity that would later be called ''positive'' and ''negative''. The Leyden jar, a type of capacitor for electrical energy in large quantities, was invented at Leiden University by Pieter van Musschenbroek in 1745. William Watson (scientist), experimenting with the Leyden jar, discovered in 1747 that a discharge of static electricity was equivalent to an electric current. In June, 1752, Benjamin Franklin promoted his investigations of electricity and theories through the famous, though extremely dangerous, experiment of flying a Kite flying during a thunderstorm. Following these experiments he invented a lightning rod and established the link between lightning and electricity. If Franklin did fly a kite in a storm, he did not do it the way it is often described (as it would have been dramatic but fatal). It was either Franklin (more frequently) or Ebenezer Kinnersley of Philadelphia (less frequently) who created the convention of positive and negative electricity. As a result of this discovery, the Chinese word for "lightning" is now also used to mean "eletricity". Franklin's observations aided later scientists such as Michael Faraday, Luigi Galvani, Alessandro Volta, Andre Marie Ampere, and Georg Ohm whose work provided the basis for modern electrical technology. The work of Faraday, Volta, Ampere, and Ohm is honored by society, in that fundamental units of electrical measurement are named after them. Volta worked with chemicals and discovered that chemical reactions could be used to create positively charged anodes and negatively charged cathodes. When a conductor was attached between these, the voltage (also known as voltage) drives a current (electricity) between them through the conductor. The potential difference between two points is measured in units of volts in recognition of Volta's work. The late 19th and early 20th century produced such giants of electrical engineering as Nikola Tesla, inventor of the induction motor and the fundamental alternating current transmission system, Samuel Morse, inventor of the telegraph; Antonio Meucci, inventor of the telephone; Thomas Edison (inventor of the phonograph and a practical incandescent light bulb); George Westinghouse, inventor of the electric locomotive; Charles Steinmetz, theoretician of alternating current. Nikola Tesla performed experiments with very high voltages that are the stuff of legend, involving ball lightning and other effects (some have been duplicated or explained; and others which have not). Nikola Tesla, inventor of the induction motor and developer of polyphase systems, contributed to the world of electrodynamics the theory of polyphase alternating current, which he used to build the first induction motor, invented in 1882. In May 1885, Westinghouse, then president of the Westinghouse Electric Company in Pittsburgh, Pennsylvania, bought the rights to Tesla's patents for polyphase alternating-current dynamos. This led to a contest in the so-called court of public opinion as to which system would be adopted as the standard for power transmission (known as the War of Currents), Edison's direct-current system or Westinghouse's alternating-current method. Edison conducted a spirited public relations campaign which included his promotion of the electric chair as a method of execution (legal). The electric chair ran on Westinghouse's AC; Edison wanted to prove that AC power was capable of killing, and should therefore be viewed by the public as inherently dangerous. This FUD campaign included the electrocution of Topsy the Elephant. AC power was eventually adopted as the standard. == Electric power == Electric power is the popular name given to electrical energy production and distribution. For most consumers, electrical energy is generated centrally by utility companies using coal, natural gas, hydropower, nuclear power or petroleum. In 2000, U.S. electric utilities had 600 gigawatts of maximum summer generating capacity including 261 GW from coal, 118 GW from natural gas, 92 GW from hydropower, 86 GW from nuclear and 41 GW from petroleum. Little generating capacity is presently based on renewable energy sources such as solar power and wind power. Some individuals and communities prefer renewable sources because there is less pollution and because users of renewable energy sources can sometimes gain a measure of economic independence from the electrical utilities. Devices powered by electrical energy include lamps, computers and the Internet, radio and television, refrigeration, air conditioning, traffic signals, electric guitars and other electronic musics, and the spark plugs in automobiles. A summary of the applications of electric energy (written for non-specialists, and briefly explaining motors, transformers, transistors, digital, etc.) is the book, ''Industrial Electronics for Engineers, Chemists, and Technicians'', by D. J. Shanefield, William Andrew Publishing (Norwich, NY), 2001. In electrical engineering, the energy in electromagnetic fields is harnessed to perform useful work—either as a method to transmit energy to the appropriate place and then convert it back into a different, useful form of energy (for instance, heat, light, or motion), or by using the presence or level of electricity to convey information. Today's electrical engineers enjoy the ability to design circuits using pre-manufactured building blocks such as power supply, resistors, capacitors, semiconductors such as transistors, and integrated circuits. An integrated circuit inside a computer, the microprocessor, performs millions of computations per second. == Electric current == A flow of electricity is called an current (electricity). A direct current (DC) is a unidirectional flow; alternating current (AC) is a flow whose time average is zero, but is not zero at all times. That definition of AC implies that the flowing electricity repeatedly changes direction. (Polarity and numerical sign (i.e. negative vs. positive) are additional terms for direction in this sense). It is often important, particularly for safety reasons, that one side of a circuit be electrically bonded to an earth terminal. Such an earth terminal is usually connected to an electrode buried in the ground. The potential of earth (Ground (electricity) ) is defined as zero by convention, and the electrical conductivity between similarly buried electrodes is considered to be low enough that all earth terminals are effectively at the same voltage. The electricity which occurs naturally within Conductor (material)s can be forced to flow, while the charges within insulators are locked in place and cannot be moved. Some electrical devices that use electrical physics are called electronics. See electrical conduction for more information about charge flow in materials. Ohm's Law is an important relationship describing the behaviour of electric currents: : where is the applied voltage, measured in volts is the current, measured in amperes is the resistance, measured in ohms For historical reasons, electricity is said to flow from the most positive part of a circuit to the most negative part. The electric current thus defined is called ''conventional current''. It is now known that, depending on the type of conductor, 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. If another definition is used - for example, "electron current" - it should be explicitly stated. == Terminology issues == In addition to its definition by physicists, the word ''electricity'' has several popular definitions which are contradictory. Rather than using the word ''electricity'' to refer to the quantity of electric charge, many sources instead say that electricity is the quantity of electromagnetic energy measured in joules or kWh. Other sources call the motion of charges within a conductor by the name ''electricity'', and they measure the quantity of electricity in terms of amperes. Still others call a wide variety of electrical phenomena by the name ''electricity'', e.g. bioelectricity, piezoelectricity, triboelectricity, etc. It is advisable to be extremely careful when interpreting texts which employ the frequently misused term "electricity" in place of the more accurate terms electric charge, electric current, electrical energy, etc. == SI electricity units == == See also == * Main: electromagnetism, electrical phenomenon (electric charge), electric power (for energy transfer using electricity), electric shock, electric chair (execution) * Things: Battery (electricity), Lightning, Conductor * Engineering: Green electricity, Electrical wiring === Electrical phenomena in nature === * Lightning * Bioelectricity — Many animals are sensitive to electric fields, some (e.g., sharks) more than others (e.g., people). Most also generate their own electric fields, and a few, like the electric eel, deliberately generate strong fields to detect or stun their prey. * Neurons in the nervous system transmit information by electrical impulses known as action potentials. * Matter — since atoms and molecules are held together by electric forces. * The Earth's magnetic field — created by electric currents circulating in the planet's core. * Sometimes due to solar flares, a phenomenon known as a power surge can be created, which can be very damaging to sensitive electrical equipment such as computers. However, such damage can be prevented by using a surge protector. == External links == * [http://amasci.com/miscon/whatis.html What is electricity?] * [http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=electricity Merriam-Webster: Electricity] * [http://www.bibliomania.com/2/9/72/119/21387/1.html Tyndall: Faraday as Discovery: Identity of Electricities] * [http://www.eia.doe.gov/fuelelectric.html US Energy Department Statistics] * [http://www.mouthshut.com/readreview/38842-1.html How to save on your electricity bills] * [http://users.pandora.be/worldstandards/electricity.htm Electricity around the world] * [http://www.tufts.edu/as/wright_center/fellows/bob_morse_04/ A Comprehensive Collection of Franklin’s Electrical Works: The Electrical Writings of Benjamin Franklin], Created and Collected by Robert A. Morse (2004) Electricity bn:বিদ্যুত্ fa:برق hi:विद्युत
Electricity
----- "there is a force between these charges that is directly proportional to the magnitude of the charge of the objects and inversely proportional to distance between them." Is that correct? Should it not rather be " ... and inversely proportional to ''the square of '' the distance between them."? The subsequent formula seems unnecessarily awkward. S. ---- Can anyone remember reading a short science fiction story about someone who is granted a wish, and decides that the best way to solve the world's problems is to abolish electricity? Unfortunately he doesn't know that electricity is what holds atoms together. His wish is granted, and the universe falls apart. If I knew the name of this story, I would add a reference to it in this article. - User:Heron *Perhaps, Electricity (Sci-fi) if it is long enough. ---- Hmm. I have to say this article is phenomenally America-centric. And pretty much glosses over everything before Ben Franklin, whose significance (on the other tentacle) to what followed, really is blown totally out of proportion. I mean, really! -- User:Cimon avaro 20:08, Sep 19, 2003 (UTC) == Removed from Current == Accuracy aside, the following 'graph does not belong in the section on Current. It may have some value elsewhere. :It is often important, particularly for safety reasons, that one side of a circuit be electrically bonded to an earth terminal. Such an earth terminal is usually connected to an electrode buried in the ground. The potential of earth (ground) is defined as zero by convention, and the electrical conductivity between similarly buried electrodes is considered to be low enough that all earth terminals are effectively at the same voltage. --User:Jerzy 01:35, 2003 Dec 12 (UTC) ==Main focus of this article ??== Many of the pointers to this page seems to mean ''electricity'' in the meaning ''electrical energy''. Perhaps there should be a separate article about electrical energy, with all relevant pointers so directed? -- User:Egil 07:46 Feb 7, 2003 (UTC) If I had started this article, I would have made it a disambiguation article with links to "electrical energy", "electrical power", "electric current", "electric charge" and all other electrical phenomena. The present article is about electric charge, so it could perhaps be merged with the article of that name. -- User:Heron I believe this article should focus on the commonest meaning of electricity, i.e. electric current. One proof of this is to look at the articles that link to here: most take the "electric current" view. It should start with a disambiguation paragraph linking to other electrical phenomena. User:Pcarbonn 19:21, 5 Sep 2004 (UTC) On the contrary, the commonest meaning of electricity is electrical energy. It is a widespread misconception that electric current is a form of energy. No, an Ampere is not a Joule. Just because many authors incorrectly give electric current the name "electricity" doesn't mean that reference works should support the error. In non-science topics, common usage *is* the correct usage, but in physics, a common misconception remains incorrect no matter how many people aquire that misconception. Physics books play by very different rules than dictionaries. ------- I agree that "Electricity" should become a disambiguation entry. In addition to articles on Electric Charge and Electrical Energy (etc.,) the present article can split off into an article about common misconceptions regarding the term Electricity. Because even the authors of many reference books have a fairly poor understanding of charge vs. energy, disambiguation becomes a proper topic for the science and education community, not just the usual Wikipedia issue. User:Wjbeaty 16:19 Dec 27, 2004 (PST) == How electricity kills == Electricity kills in either of these ways: * Current of at least 50 miliamps passing through the heart can cause it to stop. To get 50ma to the heart, there must be sufficent voltage to overcome the body's natural resistance. * The body's natural resistance can cause it to absorb the electricity and convert it to heat. Given enough power, this heat will cause the body to cook. For this, it does not matter if it is low voltage or low power, as long as the product of the two is high enough for the power to heat the body faster than it can dissipate the generated heat. As stated in the main article, Ohm's law gives the relationship between current, voltage, and resistance. When resitsance is present, both current and voltage must be non-zero for the other to exist. Power is the product of current and voltage. --User:Ssd 20:08, 13 Mar 2005 (UTC) I've tried to explain it to you, if you are not interested then too bad. Voltage DOES NOT EXIST in a physical manner, it is simply the difference of potential between two points. :That's silly. I can measure it, it exists. No, it isn't a physical substance. I can't see voltage. I can't see current. I can't see wind either, does it not exist either? Voltage, as you say, is the electrical potential between two points. If there is no potential, there will not be any current either. Neither current nor voltage alone are sufficent to describe electricity. Both must be considered. If voltage was not important, Ohm's law would also not be important. I suppose you could argue that given you have two independent variables and one dependent variable. However, which one you pick for the dependent variable is really just a matter of semantics or point of view. --User:Ssd 20:22, 13 Mar 2005 (UTC) You are misunderstanding what I am saying. When you pull out your voltmeter, you are not actually measuring voltage - you are measuring the DIFFERENCE in "pressure" between two points. In a wye connected system, for example, if your line voltage was 480v, your phase voltage would be 277v.(480/1.732, or the root of three). Now measure from phase to phase, and what would you have? exactly. --User:Vega007 By the way, no disrespect, but you CAN see current when it is arcing and sparking. Are you an electrician like myself or just an educated observer? ::When you see arcing, you are seeing voltage high enough to ionize the air and form a conductive path. If it is high current, the arc lasts longer and is thicker. If it is low current, you will see short lived thin arcs that will reoccur as the voltage becomes high enough for a new arc. (Technically, you don't see current or voltage, you see photons, but that's just being pedantic.) --User:Ssd 05:32, 16 Mar 2005 (UTC) :Voltage is a relative difference between two points. If you want to say that a single point has a voltage, then you have to choose a single reference point for the circuit, and you are implying a measurement relative to that point. That point is called ground. Although there are conventions for which point you call ground, you could technically define ''any'' point in the circuit as 0 V and measure all other points relative to it. - User:Omegatron 00:55, Mar 14, 2005 (UTC) I agree mostly with everything now here. A couple of fine points... Everything Omegatron said about voltage is exactly correct. However, when I think of voltage, I think of a power source. When I think of voltage from a power source, I think transmission line, which has (at least) two wires, and thus two points of reference from which to measure. If you grabbed those two with one hand, you'd be burned. If you grab one in each hand, there's a good chance voltage (and current) will pass through your body, and thus through your heart. For those purists that say "voltage does not exist, only current matters", I'd like to remind them that only ideal power sources can supply infinite voltage when met with high resistance, where a real power source won't get sufficent current through to matter if it can't supply the needed voltage. Likewise, the real power source when faced with zero resistance can't supply infinite current to keep voltage constant. Thus, all real power supplies have a maximum voltage and maximum current rating, and even if they are constant current (rare except battery chargers) or constant voltage (most are), when the maximum voltage or maximum current is surpassed, it will be unable to keep the other from sagging. This is why ''both'' ratings are important. It is thus incorrect to say only current or only voltage is important. This was my original point, more correctly stated. (These incremental changes from discussion like this I like to think make points clearer and help all parties see their errors and fuzzy thinking. Some of this probably should be integrated into a relevant article once it's all correct. --User:Ssd) ==Proposed focus== I was surprised to see how the focus of the article changes rapidly as you read into it. I'd suggest putting all the electric power discusions as links to those articles, and leaving "electricity" as more of a discussion of the fundamental physics. Static charge, dynamic charge, all the pith-ball-and-compass-needle history, etc. - and leave applications to other articles. --User:Wtshymanski 22:38, 16 May 2005 (UTC)
Electricity
Electricity is a property of certain subatomic particles, such as electrons and protons, that gives rise to attractive and repulsive forces between them. It is one of the four fundamental forces of nature, and is a conserved property of matter that can be quantified. Electromagnetism
See other meanings of words starting from letter:
E
EA | EB | EC | ED | EF | EG | EH | EI | EJ | EK | EL | EM | EN | EO | EP | ER | ES | ET | EU | EW | EX | EY | EZ |Words begining with Electricity:
Electricity
Electricity
Electricity
Electricity/to_do
Electricity_and_magnetism
Electricity_cell
Electricity_Commissioners
Electricity_Commission_(UK)
Electricity_distribution
Electricity_distribution
Electricity_distribution
Electricity_generation
Electricity_generation
Electricity_generation_in_Canada
Electricity_grid
Electricity_induction
Electricity_in_India
Electricity_liberalisation
Electricity_liberalization
Electricity_market
Electricity_market
Electricity_meter
Electricity_network
Electricity_pylon
Electricity_pylon
Electricity_retail
Electricity_retailer
Electricity_retailing
Electricity_safety
Electricity_supply
Electricity_Supply_Board
Electricity_Supply_Board
Electricity_therapy
Electricity_therapy
Electricity_transmission
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