Wireless energy transfer The most common form of wireless power transmission is carried out using direct induction followed by resonant magnetic induction. Other methods under consideration are electromagnetic radiation in the form of microwaves or lasers and electrical conduction through natural media. Electric energy transfer An electric current flowing through a conductor, such as a wire, carries electrical energy. In a direct current circuit, if the current is continuous, the fields are constant; there is a condition of stress in the space surrounding the conductor, which represents stored electric and magnetic energy, just as a compressed spring or a moving mass represents stored energy. Any change in the electrical conditions of the circuit, whether internal or external involves a readjustment of the stored magnetic and electric field energy of the circuit, that is, a so-called transient. Electromagnetic induction Electrodynamic induction method Electromagnetic radiation
Static electricity Contact with the slide has left this child's hair positively charged so that the individual hairs repel one another. The hair can also be attracted to the negatively charged slide surface. Static electricity is an imbalance of electric charges within or on the surface of a material. Causes of static electricity Materials are made of atoms that are normally electrically neutral because they contain equal numbers of positive charges (protons in their nuclei) and negative charges (electrons in "shells" surrounding the nucleus). Contact-induced charge separation Pressure-induced charge separation Applied mechanical stress generates a separation of charge in certain types of crystals and ceramics molecules. Heat-induced charge separation Heating generates a separation of charge in the atoms or molecules of certain materials. Charge-induced charge separation A charged object brought close to an electrically neutral object causes a separation of charge within the neutral object. Static discharge
Tesla turbine Tesla turbine The Tesla turbine is a bladeless centripetal flow turbine patented by Nikola Tesla in 1913. It is referred to as a bladeless turbine because it uses the boundary layer effect and not a fluid impinging upon the blades as in a conventional turbine. Description View of Tesla turbine "bladeless" design Tesla wrote, "This turbine is an efficient self-starting prime mover which may be operated as a steam or mixed fluid turbine at will, without changes in construction and is on this account very convenient. This turbine can also be successfully applied to condensing plants operating with high vacuum. All the plates and washers are fitted on and keyed to a sleeve threaded at the ends and equipped with nuts and collars for drawing the thick end-plates together or, if desired, the collars may be simply forced onto it and the ends upset. View of Tesla turbine system As diagrammed, a Tesla turbine installation is: An efficient Tesla turbine requires close spacing of the disks. Tesla
Van de Graaff generator A Van de Graaff generator is an electrostatic generator which uses a moving belt to accumulate very high amounts of electrical potential on a hollow metal globe on the top of the stand. It was invented by American physicist Robert J. Van de Graaff in 1929. The potential difference achieved in modern Van de Graaff generators can reach 5 megavolts. A Van de Graaff generator operates by transferring electric charge from a moving belt to a terminal. Description Schematic view of a classical Van de Graaff-generator. 1) hollow metal sphere 2) upper electrode 3) upper roller (for example an acrylic glass) 4) side of the belt with positive charges 5) opposite side of the belt with negative charges 6) lower roller (metal) 7) lower electrode (ground) 8) spherical device with negative charges, used to discharge the main sphere 9) spark produced by the difference of potentials Another method for building Van de Graaff generators is to use the triboelectric effect. History Patents
Plasma globe A plasma globe with filaments extending from the inner sphere to the outer. Description The effect of a conducting object (such as a hand) in close proximity with the plasma globe glass Some globes have a control knob that varies the amount of power going to the center electrode. Placing a finger tip on the glass creates an attractive spot for the energy to flow, because the conductive human body (having non-ohmic resistance of about 1000 ohms at room temperature) is more easily polarized than the dielectric material around the electrode (i.e. the gas within the globe) providing an alternative discharge path having less resistance. Much of the movement of the filaments is due to heating of the gas around the filament. An electric current is produced within any conductive object near the orb. The globe is prepared by pumping out as much air as is practical. The neon available for purchase for a neon-sign shop often comes in glass flasks at the pressure of a partial vacuum. In U.S.
Electrostatic generator An electrostatic generator, or electrostatic machine, is an electromechanical generator that produces static electricity, or electricity at high voltage and low continuous current. The knowledge of static electricity dates back to the earliest civilizations, but for millennia it remained merely an interesting and mystifying phenomenon, without a theory to explain its behavior and often confused with magnetism. By the end of the 17th Century, researchers had developed practical means of generating electricity by friction, but the development of electrostatic machines did not begin in earnest until the 18th century, when they became fundamental instruments in the studies about the new science of electricity. Electrostatic generators operate by using manual (or other) power to transform mechanical work into electric energy. Description Electrostatic machines are typically used in science classrooms to safely demonstrate electrical forces and high voltage phenomena. History
Nikola Tesla: The Genius Who Lit the World This is the documentary film about Nikola Tesla, the scientist and inventor, one of the greatest men in history. Nikola Tesla was born on July 10,1856 in Smiljan, Lika in what later became Yugoslavia. His father, Milutin Tesla was a Serbian orthodox priest and his mother Djuka Mandic was an inventor in her own right of household appliances. Tesla studied at the Polytechnic Institute in Graz, Austria and the University of Prague. Before going to America, Tesla joined Continental Edison Company in Paris where he designed dynamos. Young Nikola Tesla came to the United States in 1884. Direct current flows continuously in one direction; alternating current changes direction 50 or 60 times per second, and can be stepped up to very high voltage levels, minimizing power loss across great distances. Tesla's A-C induction motor is widely used throughout the world in industry and household appliances. Watch the full documentary now
Wimshurst machine The Wimshurst influence machine is an electrostatic generator, a machine for generating high voltages developed between 1880 and 1883 by British inventor James Wimshurst (1832–1903). It has a distinctive appearance with two large contra-rotating discs mounted in a vertical plane, two crossed bars with metallic brushes, and a spark gap formed by two metal spheres. Description These machines belong to a class of electrostatic generators called influence machines, which separate electric charges through electrostatic induction, or influence, not depending on friction for their operation. Earlier machines in this class were developed by Wilhelm Holtz (1865 and 1867), August Toepler (1865), J. Robert Voss (1880), and others. In a Wimshurst machine, the two insulated discs and their metal sectors rotate in opposite directions passing the crossed metal neutralizer bars and their brushes. Operation Animation See also References "History of Electrostatic Generators".
Nikola Tesla Nikola Tesla (Serbian Cyrillic: Никола Тесла; 10 July 1856 – 7 January 1943) was a Serbian-American inventor, electrical engineer, mechanical engineer, physicist, and futurist who is best known for his contributions to the design of the modern alternating current (AC) electricity supply system. Born and raised in the Austrian Empire, Tesla received an advanced education in engineering and physics in the 1870s and gained practical experience in the early 1880s working in telephony and at Continental Edison in the new electric power industry. He emigrated to the United States in 1884, where he would become a naturalized citizen. He worked for a short time at the Edison Machine Works in New York City before he struck out on his own. With the help of partners to finance and market his ideas, Tesla set up laboratories and companies in New York to develop a range of electrical and mechanical devices. Early years Tesla's baptismal record, 28 June 1856 Working at Edison A move to the US
Electrophorus For the genus of fish family Electrophoridae, see electric eel. Electrophorus from the 1800s. An electrophorus is a simple manual capacitive generator used to produce electrostatic charge via the process of electrostatic induction. A first version of it was invented in 1762 by Swedish professor Johan Carl Wilcke, but Italian scientist Alessandro Volta improved and popularized the device in 1775, and is sometimes erroneously credited with its invention. The word electrophorus was coined by Volta from the Greek ήλεκτρον ('elektron'), and ϕέρω ('phero'), meaning 'electricity bearer'. Description and operation The electrophorus consists of a dielectric plate (originally a 'cake' of resinous material such as pitch or wax, but in modern versions plastic is used) and a metal plate with an insulating handle. The dielectric plate is first charged through the triboelectric effect by rubbing it with fur or cloth. Showing induced charge on plate before grounding.