Dictionary
a physical phenomenon associated with stationary or moving electrons and protons energy made available by the flow of electric charge through a conductor "they built a car that runs on electricity" keen and shared excitement "the stage crackled with electricity whenever she was on it"
|
Wikipedia
Electricity is a general term applied to phenomena involving a fundamental property of matter called an ''electric charge''. This article will introduce and explain some of the basic principles of electricity. In casual usage, the term ''electricity'' is applied to several related concepts that are better identified by more precise terms. Some of these concepts are the subjects of other articles: Electric charge: the basic concept involved in electricity, introduced in this article, but discussed more extensively in a separate article.Current (electricity) Electric current: a movement or flow of electrically charged particles, introduced in this article, but discussed more extensively in a separate article.Electrical energy: a form of energy related to the position of an electric charge in an electric field.Electric power: electrical energy as it is delivered to individual, commercial and industrial customers for use in operating equipment, and providing heat and illumination.Electric potential or volt voltage: a measure of the force available to cause electric current to flow. Bioelectromagnetism Bioelectricity: electrical phenomena within living organisms. Piezoelectricity: the ability of certain crystals to generate a voltage in response to applied mechanical stress. triboelectric effect Triboelectricity: electric charge taken on by contact or friction between two different materials. strikes during a night-time thunderstorm. Notice that you are not actually seeing electric charge; you are seeing energy being radiated as light as the air of Earth's atmosphere is shifted from gas to plasma and back. ]]
Electric charge - Electric charge is a property of certain subatomic particles (e.g., electrons and protons) which interacts with electromagnetic fields and causes attractive and repulsive forces between them. Electric charge 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 chargecharge of electricity" and "quantity of charge." There are two types of charge: we call one kind of charge 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 charge 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 -
Ancient - According to ThalesThales of Miletus, writing ''circa'' 600 BCE, a form of electricity was known to the Ancient GreeceAncient Greeks, 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 languageGreek ''ēlektron'' = "amber", which came from an old root (linguistics)root ''ēlek-'' = "shine".An object found in Iraq in 1938, dated to about 250 BCE and called the Baghdad Battery, resembles a galvanic cell and is believed by some to have been used for electroplating. The conjecture that this or other ancient artifacts had an electrical function remains unproven, and such proposed ancient knowledge bears no known continuous relationship to the development of modern electrical technology.
Modern - In 1600 the English scientist William Gilbert returned to the subject in ''De Magnete'', and coined the modern Latin word ''electricus'' from !''ηλε&kappa ;τρον''? (''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 conductor (material)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)William Watson, 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 flyingkite 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.Franklin's observations aided later scientists such as Michael Faraday, Luigi Galvani, Alessandro Volta, Andre Marie AmpereAndré-Marie Ampère, and Georg OhmGeorg Simon 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 voltagedifference in the electrical potential (also known as voltage) drives a current (electricity)current between them through the conductor. The potential difference between two points is measured in units of volts in recognition of Volta's work. The invention of the telegraph showed that commercial and practical use could be made of electrical phenomena. By the end of the 19th century electrical engineering became a distinct profession, separate from the physicist or inventor. The late 19th and early 20th century produced such giants of electrical engineering as Nikola Tesla, inventor of the polyphase induction motor; Samuel Morse, inventor of the telegraph; Antonio Meucci, an 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; Alexander Graham Bell, another inventor of the telephone and founder of a sucessful telephone business. The rapid advance of electrical technology in the latter 19th and early 20th centuries lead to commercial rivalry such as the so-called War of CurrentsWar of the Currents), between Edison's direct-current system or Westinghouse's alternating-current method. Often concurrent research in widely scattered locations lead to multiple claims to the invention of a device or system.
Electric current - The electric charge which occurs naturally within Conductor (material)conductors can be forced to flow, while the charges within insulators are locked in place and cannot be moved. Devices that use charge flow principles in materials are called electronicselectronic devices. A flow of electric charge is called an current (electricity)electric current. A direct current (DC) is a unidirectional flow; alternating current (AC) is a flow whose time average is zero, but whose energy capability (RMS level) is not zero. With AC the electric current repeatedly changes direction. See electrical conductionOhm's Law is an important relationship describing the behaviour of electric currents::where is the applied voltage, measured in !volts
|
|
Websites
Unravelit - Savings Made Simple
Unravelit is an independent and impartial online service that helps you make the right choices for your energy, insurance and financial needs. We have built a range of comparison tools that help you find the right deal, for you, based on your personal preferences. All our services are designed to help you get to the right decisions, quickly and easily.
http://www.unravelit.com/
SCADA for Electric Utilities
iPower SCADA provides a safe and intuitive environment for electricity network operations. Intelligent configuration reduces implementation costs while producing systems that are consistent and easy to maintain. An open, client-server architecture with redundancy, complete a safe and robust SCADA system.
http://www.i-scada.com/
Nikola Tesla: Forgotten American Scientist
Teacher, John Wagner and his third grade students donate bronze bust of Tesla to 19 major universities.
http://www.ntesla.org/
International Centre for Hydropower
The international Centre for Hydropower 8ICH) is a non-profit association whose objective is to act as a joint international forum for industry and institutions in the field of hydropower and related areas. The centre supports the hydropower industry by gathering, developing and marketing know-how on environmental, technoclogical, economic and administrative aspects of hydropower.
http://www.ich.no/
www.westmark.nl
Westmark BV was founded in 1992 as a trading company serving the industry. Westmark has a vision for the future; the company was instrumental in a number of innovative and revolutionary products, which became the trendsetters for the industry. Over the past years the company has developed a number of divisions each serving its' own markets. Most of the activities consist of the marketing of sophisticated technical products from well-established companies. Westmark's philosophy for the future is to remain in the forefront of new developments and novelties in the various markets. Fuel catalyst Renergi-mergi. This catalyst improves combustion in marine propulsion plants. It reduces maintenance costs and overhaul intervals will be longer. The daily fuel consumption will drop considerably. Westmark is producer of Cablesafe; an “S” shaped hook to suspend cables during shut down works, temporary electrical installations, events- and stage rigging, offshore platforms shipbuilding etc.
http://www.westmark.nl/
Entreprises d'Equipement électrique
Chambre syndicale d'équipement électrique de Paris et sa région
http://www.cseee.fr/
Viva Solar Inc.
Viva Solar Inc. is a manufacturer of monocrystal Silicon photovoltaic solar cells, modules and systems.
http://www.vivasolar.com/
Electricity Association
Association of major electricity companies in the UK.
http://www.electricity.org.uk/
Museum of Science
Features a revolving schedule of Imax films, temporary exhibitions and planetarium shows. Includes online exhibits.
http://www.mos.org/
The Electricity Journal and The Electricity Daily
Jopurnals published by Elsevier with history and online substriptions.
http://www.electricity-online.com/
Science Made Simple
Kids get simple, detailed answers to common science questions. Plus great science projects and experiments, science news and interactive unit measurement conversions.
http://www.sciencemadesimple.com/
Electricity Forum
Organization that publishes books, sponsors seminars and trade shows, and offers training on electrical systems, concentrating on Canada and the USA. List of courses, seminars, and a company directory.
http://www.electricityforum.com/
|
|