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In fluid dynamics, two types of stream function (or streamfunction) are defined:
The two-dimensional (or Lagrange) stream function, introduced by Joseph Louis Lagrange in 1781, is defined for incompressible (divergence-free), two-dimensional flows.
The Stokes stream function, named after George Gabriel Stokes, is defi... | Wikipedia/Stream_function |
In mathematics, there are several functions known as Kummer's function. One is known as the confluent hypergeometric function of Kummer. Another one, defined below, is related to the polylogarithm. Both are named for Ernst Kummer.
Kummer's function is defined by
Λ
... | Wikipedia/Kummer's_function |
In mathematics, in particular linear algebra, the matrix determinant lemma computes the determinant of the sum of an invertible matrix A and the dyadic product, u vT, of a column vector u and a row vector vT.
== Statement ==
Suppose A is an invertible square matrix and u, v are column vectors. Then the matrix determi... | Wikipedia/Matrix_determinant_lemma |
A generator in electrical circuit theory is one of two ideal elements: an ideal voltage source, or an ideal current source. These are two of the fundamental elements in circuit theory. Real electrical generators are most commonly modelled as a non-ideal source consisting of a combination of an ideal source and a resi... | Wikipedia/Generator_(circuit_theory) |
In electrical circuit theory, a port is a pair of terminals connecting an electrical network or circuit to an external circuit, as a point of entry or exit for electrical energy. A port consists of two nodes (terminals) connected to an outside circuit which meets the port condition – the currents flowing into the two ... | Wikipedia/Port_(circuit_theory) |
An equivalent impedance is an equivalent circuit of an electrical network of impedance elements which presents the same impedance between all pairs of terminals as did the given network. This article describes mathematical transformations between some passive, linear impedance networks commonly found in electronic cir... | Wikipedia/Equivalent_impedance_transforms |
In materials science, effective medium approximations (EMA) or effective medium theory (EMT) pertain to analytical or theoretical modeling that describes the macroscopic properties of composite materials. EMAs or EMTs are developed from averaging the multiple values of the constituents that directly make up the composi... | Wikipedia/Effective_medium_approximations |
In electrical engineering, the distributed-element model or transmission-line model of electrical circuits assumes that the attributes of the circuit (resistance, capacitance, and inductance) are distributed continuously throughout the material of the circuit. This is in contrast to the more common lumped-element mode... | Wikipedia/Distributed-element_model |
Small-signal modeling is a common analysis technique in electronics engineering used to approximate the behavior of electronic circuits containing nonlinear devices, such as diodes, transistors, vacuum tubes, and integrated circuits, with linear equations. It is applicable to electronic circuits in which the AC signal... | Wikipedia/Small-signal_model |
In circuit design, the Y-Δ transform, also written wye-delta and also known by many other names, is a mathematical technique to simplify the analysis of an electrical network. The name derives from the shapes of the circuit diagrams, which look respectively like the letter Y and the Greek capital letter Δ. This circuit... | Wikipedia/Y-Δ_transform |
The star-mesh transform, or star-polygon transform, is a mathematical circuit analysis technique to transform a resistive network into an equivalent network with one less node. The equivalence follows from the Schur complement identity applied to the Kirchhoff matrix of the network.
The equivalent impedance betweens n... | Wikipedia/Star-mesh_transform |
In electronics, a two-port network (a kind of four-terminal network or quadripole) is an electrical network (i.e. a circuit) or device with two pairs of terminals to connect to external circuits. Two terminals constitute a port if the currents applied to them satisfy the essential requirement known as the port conditio... | Wikipedia/Two-port_network |
Reciprocity in electrical networks is a property of a circuit that relates voltages and currents at two points. The reciprocity theorem states that the current at one point in a circuit due to a voltage at a second point is the same as the current at the second point due to the same voltage at the first. The reciproc... | Wikipedia/Reciprocity_(electrical_networks) |
A variable-gain (VGA) or voltage-controlled amplifier (VCA) is an electronic amplifier that varies its gain depending on a control voltage (often abbreviated CV).
VCAs have many applications, including audio level compression, synthesizers and amplitude modulation.
A crude example is a typical inverting op-amp configur... | Wikipedia/Voltage_controlled_amplifier |
A delta-wye transformer is a type of three-phase electric power transformer design that employs delta-connected windings on its primary and wye/star connected windings on its secondary. A neutral wire can be provided on wye output side. It can be a single three-phase transformer, or built from three independent single... | Wikipedia/Delta-wye_transformer |
Home energy storage refers to residential energy storage devices that store electrical energy locally for later consumption. Usually, electricity is stored in lithium-ion rechargeable batteries, controlled by intelligent software to handle charging and discharging cycles. Companies are also developing smaller flow batt... | Wikipedia/Home_energy_storage |
Electrical insulation papers are specific types of paper that are used as electrical insulation. They are used in many applications due to the outstanding electrical properties of pure cellulose. Cellulose is a good insulator and is also polar, having a relative permittivity significantly greater than 1. Electrical pap... | Wikipedia/Transformerboard |
Toroidal inductors and transformers are inductors and transformers which use magnetic cores with a toroidal (ring or donut) shape. They are passive electronic components, consisting of a circular ring or donut shaped magnetic core of ferromagnetic material such as laminated iron, iron powder, or ferrite, around which ... | Wikipedia/Toroidal_inductors_and_transformers |
Voltage transformers (VT), also called potential transformers (PT), are a parallel-connected type of instrument transformer. They are designed to present a negligible load to the supply being measured and have an accurate voltage ratio and phase relationship to enable accurate secondary connected metering.
== Ratio =... | Wikipedia/Voltage_transformer |
Energy subsidies are measures that keep prices for customers below market levels, or for suppliers above market levels, or reduce costs for customers and suppliers. Energy subsidies may be direct cash transfers to suppliers, customers, or related bodies, as well as indirect support mechanisms, such as tax exemptions an... | Wikipedia/Energy_subsidy |
A rotary variable differential transformer (RVDT) is a type of electrical transformer used for measuring angular displacement. The transformer has a rotor which can be turned by an external force. The transformer acts as an electromechanical transducer that outputs an alternating current (AC) voltage proportional to th... | Wikipedia/Rotary_variable_differential_transformer |
A zigzag transformer winding is a special-purpose transformer winding with a zigzag or "interconnected star" connection, such that each output is the vector sum of two (2) phases offset by 120°. It is used as a grounding transformer, creating a missing neutral connection from an ungrounded 3-phase system to permit the ... | Wikipedia/Zigzag_transformer |
Transformer oil, a type of insulating and cooling oil used in transformers and other electrical equipment, needs to be tested periodically to ensure that it is still fit for purpose. This is because it tends to deteriorate over time. Testing sequences and procedures are defined by various international standards, many ... | Wikipedia/Transformer_oil_testing |
A Scott-T transformer or Scott connection is a type of circuit used to produce two-phase electric power (2 φ, 90 degree phase rotation) from a three-phase (3 φ, 120 degree phase rotation) source, or vice versa. The Scott connection evenly distributes a balanced load between the phases of the source. The Scott three-pha... | Wikipedia/Scott-T_transformer |
A trigger transformer is a small, usually ferrite cored transformer or autotransformer used in applications requiring a high voltage pulse, typically to start ionization of a gas to allow a current to pass.
== Uses ==
Trigger transformer cores may be utilized in a unipolar (electromagnetic flux strictly positive or ... | Wikipedia/Trigger_transformer |
A padmount or pad-mounted transformer is a ground-mounted electric power distribution transformer in a locked steel cabinet mounted on a concrete pad. Since all energized connection points are securely enclosed in a grounded metal housing, a padmount transformer can be installed in places that do not have room for a f... | Wikipedia/Pad-mounted_transformer |
Droop speed control is a control mode used for AC electrical power generators, whereby the power output of a generator reduces as the line frequency increases. It is commonly used as the speed control mode of the governor of a prime mover driving a synchronous generator connected to an electrical grid. It works by cont... | Wikipedia/Droop_speed_control |
The Parametric transformer (or paraformer) is a particular type of transformer. It transfers the power from primary to secondary Windings not by mutual inductance coupling but by a variation of a parameter in its magnetic circuit. First described by Wanlass, et al., 1968.
Assuming Faraday's law of induction,
... | Wikipedia/Parametric_transformer |
In electrical engineering, an autotransformer is an electrical transformer with only one winding. The "auto" (Greek for "self") prefix refers to the single coil acting alone. In an autotransformer, portions of the same winding act as both the primary winding and secondary winding sides of the transformer. In contrast, ... | Wikipedia/Autotransformer |
Electric energy consumption is energy consumption in the form of electrical energy. About a fifth of global energy is consumed as electricity: for residential, industrial, commercial, transportation and other purposes.
The global electricity consumption in 2022 was 24,398 terawatt-hour (TWh), almost exactly three time... | Wikipedia/Electric_energy_consumption |
Grid energy storage, also known as large-scale energy storage, are technologies connected to the electrical power grid that store energy for later use. These systems help balance supply and demand by storing excess electricity from variable renewables such as solar and inflexible sources like nuclear power, releasing i... | Wikipedia/Grid_energy_storage |
A voltage regulator is a system designed to automatically maintain a constant voltage. It may use a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.
Electron... | Wikipedia/Constant-potential_transformer |
Energy demand management, also known as demand-side management (DSM) or demand-side response (DSR), is the modification of consumer demand for energy through various methods such as financial incentives and behavioral change through education.
Usually, the goal of demand-side management is to encourage the consumer to ... | Wikipedia/Energy_demand_management |
High-voltage transformer fire barriers, also known as transformer firewalls, transformer ballistic firewalls, or transformer blast walls, are outdoor countermeasures against a fire or explosion involving a single transformer from damaging adjacent transformers. These barriers compartmentalize transformer fires and expl... | Wikipedia/High-voltage_transformer_fire_barriers |
A battery energy storage system (BESS), battery storage power station, battery energy grid storage (BEGS) or battery grid storage is a type of energy storage technology that uses a group of batteries in the grid to store electrical energy. Battery storage is the fastest responding dispatchable source of power on electr... | Wikipedia/Battery_energy_storage_system |
A transformer is a device that transfers electrical energy from one circuit to another.
Transformer may also refer to:
== Art and entertainment ==
Characters in the Transformers franchise
Transformer (film), a 2017 Canadian documentary
Transformer, a 1986 Sega arcade game
Transformer: The Deep Chemistry of Life and D... | Wikipedia/Transformer_(disambiguation) |
A current transformer (CT) is a type of transformer that reduces or multiplies alternating current (AC), producing a current in its secondary which is proportional to the current in its primary.
Current transformers, along with voltage or potential transformers, are instrument transformers, which scale the large values... | Wikipedia/Current_transformer |
In energy economics and ecological energetics, energy return on investment (EROI), also sometimes called energy returned on energy invested (ERoEI), is the ratio of the amount of usable energy (the exergy) delivered from a particular energy resource to the amount of exergy used to obtain that energy resource.
Arithmeti... | Wikipedia/Energy_return_on_investment |
Transformer oil or insulating oil is an oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil-filled wet transformers, some types of high-voltage capacitors, fluorescent lamp ballasts, and some types of high-voltage switches and circuit breakers. It functions to i... | Wikipedia/Transformer_oil |
Condition monitoring of transformers in electrical engineering is the process of acquiring and processing data related to various parameters of transformers to determine their state of quality and predict their failure. This is done by observing the deviation of the transformer parameters from their expected values. Tr... | Wikipedia/Condition_monitoring_of_transformers |
Voltage control and reactive power management are two facets of an ancillary service that enables reliability of the transmission networks and facilitates the electricity market on these networks. Both aspects of this activity are intertwined (voltage change in an alternating current (AC) network is effected through pr... | Wikipedia/Voltage_control_and_reactive_power_management |
The linear variable differential transformer (LVDT) – also called linear variable displacement transformer, linear variable displacement transducer, or simply differential transformer – is a type of electrical transformer used for measuring linear displacement (position along a given direction). It is the base of LVDT-... | Wikipedia/Linear_variable_differential_transformer |
Various types of electrical transformer are made for different purposes. Despite their design differences, the various types employ the same basic principle as discovered in 1831 by Michael Faraday, and share several key functional parts.
== Power transformer ==
=== Laminated core ===
This is the most common type ... | Wikipedia/Transformer_types |
In an electric power system, automatic generation control (AGC) is a system for adjusting the power output of multiple generators at different power plants, in response to changes in the load. Since a power grid requires that generation and load closely balance moment by moment, frequent adjustments to the output of ge... | Wikipedia/Automatic_generation_control |
A buck–boost transformer is a type of transformer used to make adjustments to the voltage applied to alternating current equipment. Buck–boost connections are used in several places such as uninterruptible power supply (UPS) units for computers and in the tanning bed industry.
Buck–boost transformers can be used t... | Wikipedia/Buck–boost_transformer |
A flyback transformer (FBT), also called a line output transformer (LOPT), is a special type of electrical transformer. It was initially designed to generate high-voltage sawtooth signals at a relatively high frequency. In modern applications, it is used extensively in switched-mode power supplies for both low (3 V) an... | Wikipedia/Flyback_transformer |
An isolation transformer is a transformer used to transfer electrical power from a source of alternating current (AC) power to some equipment or device while isolating the powered device from the power source, usually for safety reasons or to reduce transients and harmonics. Isolation transformers provide galvanic isol... | Wikipedia/Isolation_transformer |
A rotary (rotatory) transformer is a specialized transformer used to couple electrical signals between two parts that rotate in relation to each other. They may be either cylindrical or 'pancake' shaped.
Slip rings can be used for the same purpose, but are subject to friction, wear, intermittent contact, and limitation... | Wikipedia/Rotary_transformer |
A variable-frequency transformer (VFT) is used to transmit electricity between two (asynchronous or synchronous) alternating current frequency domains. The VFT is a relatively recent development. Most asynchronous grid inter-ties use high-voltage direct current converters, while synchronous grid inter-ties are connecte... | Wikipedia/Variable-frequency_transformer |
An amorphous metal transformer (AMT) is a type of energy efficient transformer found on electric grids. The magnetic core of this transformer is made with a ferromagnetic amorphous metal.
The typical material (Metglas) is an alloy of iron with boron, silicon, and phosphorus in the form of thin (e.g. 25 μm) foils rapidl... | Wikipedia/Amorphous_metal_transformer |
An Austin ring transformer is a special type of isolation transformer with low capacitance between the primary and secondary windings and high isolation.
== Etymology ==
It is named after its inventor, Arthur O. Austin.
== Background ==
AM radio stations that broadcast in the medium frequency (MF) and low frequency... | Wikipedia/Austin_transformer |
A grounding transformer or earthing transformer is a type of auxiliary transformer used in three-phase electric power systems to provide a ground path to either an ungrounded wye or a delta-connected system. Grounding transformers are part of an earthing system of the network. They let three-phase (delta connected) sys... | Wikipedia/Grounding_transformer |
Planar transformers are high frequency transformers used in isolated switchmode power supplies operating at high frequency. As opposed to conventional "wire-wound-on-a-bobbin" transformers, planar transformers usually contain winding turns made of thin copper sheets riveted together at the ends of turns in the case of ... | Wikipedia/Planar_transformer |
In a typical power distribution grid, electric transformer power loss typically contributes to about 40-50% of the total transmission and distribution loss. Energy efficient transformers are therefore an important means to reduce transmission and distribution loss. With the improvement of electrical steel (silicon stee... | Wikipedia/Energy_efficient_transformer |
Instrument transformers are high accuracy class electrical devices used to isolate or transform voltage or current levels. The most common usage of instrument transformers is to operate instruments or metering from high voltage or high current circuits, safely isolating secondary control circuitry from the high voltage... | Wikipedia/Instrument_transformer |
A solid-state transformer (SST), power electronic transformer (PET), or electronic power transformer is an AC-to-AC converter, a type of electric power converter that replaces a conventional transformer used in AC electric power distribution. It is more complex than a conventional transformer operating at utility frequ... | Wikipedia/Solid-state_transformer |
Various types of electrical transformer are made for different purposes. Despite their design differences, the various types employ the same basic principle as discovered in 1831 by Michael Faraday, and share several key functional parts.
== Power transformer ==
=== Laminated core ===
This is the most common type ... | Wikipedia/Pulse_transformer |
A distribution transformer or service transformer provides a final voltage transformation in the electric power distribution system, stepping down the voltage used in the distribution lines to the level used by the customer.
The invention of a practical, efficient transformer made AC power distribution feasible; a syst... | Wikipedia/Distribution_transformer |
Renewable Energy Payments are a competitive alternative to Renewable Energy Credits (REC's).
Although the intent with both methods is the same, to stimulate growth in the alternative and renewable energy space, REP's have proven to offer benefits to local jobs, businesses and economies while making the growth fundable ... | Wikipedia/Renewable_Energy_Payments |
The transformer utilization factor (TUF) of a rectifier circuit is defined as the ratio of the DC power available at the load resistor to the AC rating of the secondary coil of a transformer.
T
.
U
.
F
=
P
... | Wikipedia/Transformer_utilization_factor |
Variable renewable energy (VRE) or intermittent renewable energy sources (IRES) are renewable energy sources that are not dispatchable due to their fluctuating nature, such as wind power and solar power, as opposed to controllable renewable energy sources, such as dammed hydroelectricity or bioenergy, or relatively con... | Wikipedia/Variable_renewable_energy |
Steinmetz's equation, sometimes called the power equation, is an empirical equation used to calculate the total power loss (core losses) per unit volume in magnetic materials when subjected to external sinusoidally varying magnetic flux. The equation is named after Charles Steinmetz, a German-American electrical engine... | Wikipedia/Steinmetz's_equation |
The Feynman Lectures on Physics is a physics textbook based on a great number of lectures by Richard Feynman, a Nobel laureate who has sometimes been called "The Great Explainer". The lectures were presented before undergraduate students at the California Institute of Technology (Caltech), during 1961–1964. The book's... | Wikipedia/Feynman_Lectures_on_Physics |
The Canadian Journal of Physics is a monthly peer-reviewed scientific journal covering research in physics. It was established in 1929 as the Canadian Journal of Research, Section A: Physical Sciences, obtaining its current title in 1951. The journal is published monthly by the NRC Research Press and edited by Robert ... | Wikipedia/Canadian_Journal_of_Physics |
Computer Physics Communications is a peer-reviewed scientific journal published by Elsevier under the North-Holland imprint.
The journal focuses on computational methodology, numerical analysis and hardware and software development in support of physics and physical chemistry.
According to the Journal Citation Reports,... | Wikipedia/Computer_Physics_Communications |
The Hoyle–Narlikar theory of gravity is a Machian and conformal theory of gravity proposed by Fred Hoyle and Jayant Narlikar that originally fits into the quasi steady state model of the universe.
The gravitational constant G is arbitrary and is determined by the mean density of matter in the universe. The theory was i... | Wikipedia/Hoyle–Narlikar_theory_of_gravity |
Nuclear Physics A, Nuclear Physics B, Nuclear Physics B: Proceedings Supplements and discontinued Nuclear Physics are peer-reviewed scientific journals published by Elsevier. The scope of Nuclear Physics A is nuclear and hadronic physics, and that of Nuclear Physics B is high energy physics, quantum field theory, stat... | Wikipedia/Nuclear_Physics_B:_Proceedings_Supplements |
In mathematical analysis, the Dirac delta function (or δ distribution), also known as the unit impulse, is a generalized function on the real numbers, whose value is zero everywhere except at zero, and whose integral over the entire real line is equal to one. Thus it can be represented heuristically as
... | Wikipedia/Dirac_function |
In relativistic physics, the electromagnetic stress–energy tensor is the contribution to the stress–energy tensor due to the electromagnetic field. The stress–energy tensor describes the flow of energy and momentum in spacetime. The electromagnetic stress–energy tensor contains the negative of the classical Maxwell str... | Wikipedia/Electromagnetic_stress-energy_tensor |
In mathematics, a tensor is an algebraic object that describes a multilinear relationship between sets of algebraic objects associated with a vector space. Tensors may map between different objects such as vectors, scalars, and even other tensors. There are many types of tensors, including scalars and vectors (which ar... | Wikipedia/Tensor_transformation_law |
In mathematics, particularly in linear algebra, tensor analysis, and differential geometry, the Levi-Civita symbol or Levi-Civita epsilon represents a collection of numbers defined from the sign of a permutation of the natural numbers 1, 2, ..., n, for some positive integer n. It is named after the Italian mathematicia... | Wikipedia/Levi-Civita_tensor |
The magnetic radiation reaction force is a force on an electromagnet when its magnetic moment changes. One can derive an electric radiation reaction force for an accelerating charged particle caused by the particle emitting electromagnetic radiation. Likewise, a magnetic radiation reaction force can be derived for an a... | Wikipedia/Magnetic_radiation_reaction_force |
Clusters in physics refers to small, polyatomic particles. Any particle made of between 3 × 100 and 3 × 107 atoms is considered a cluster.
The term can also refer to the organization of protons and neutrons within an atomic nucleus, e.g. the alpha particle (also known as "α-cluster"), consisting of two protons and two... | Wikipedia/Cluster_(physics) |
New Journal of Physics is an online-only, open-access, peer-reviewed scientific journal covering research in all aspects of physics, as well as interdisciplinary topics where physics forms the central theme. The journal was established in 1998 and is a joint publication of the Institute of Physics and the Deutsche Phys... | Wikipedia/New_Journal_of_Physics |
In chemistry, a hypervalent molecule (the phenomenon is sometimes colloquially known as expanded octet) is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells. Phosphorus pentachloride (PCl5), sulfur hexafluoride (SF6), chlorine trifluoride (ClF3... | Wikipedia/Hypervalent_molecule |
In computational chemistry, a water model is used to simulate and thermodynamically calculate water clusters, liquid water, and aqueous solutions with explicit solvent, often using molecular dynamics or Monte Carlo methods. The models describe intermolecular forces between water molecules and are determined from quantu... | Wikipedia/Water_model |
In physics and chemistry, an equation of state is a thermodynamic equation relating state variables, which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature, or internal energy. Most modern equations of state are formulated in the Helmholtz free energy. Equatio... | Wikipedia/PVT_(physics) |
In chemistry, a salt bridge is a combination of two non-covalent interactions: hydrogen bonding and ionic bonding (Figure 1). Ion pairing is one of the most important noncovalent forces in chemistry, in biological systems, in different materials and in many applications such as ion pair chromatography. It is a most com... | Wikipedia/Salt_bridge_(protein_and_supramolecular) |
An intramolecular force (from Latin intra- 'within') is any force that binds together the atoms making up a molecule. Intramolecular forces are stronger than the intermolecular forces that govern the interactions between molecules.
== Types ==
The classical model identifies three main types of chemical bonds — ionic,... | Wikipedia/Intramolecular_force |
An intermolecular force (IMF; also secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction
or repulsion which act between atoms and other types of neighbouring particles (e.g. atoms or ions). Intermolecular forces are weak relative to intramolecular ... | Wikipedia/Debye_force |
In chemistry, the term substrate is highly context-dependent. Broadly speaking, it can refer either to a chemical species being observed in a chemical reaction, or to a surface on which other chemical reactions or microscopy are performed.
In the former sense, a reagent is added to the substrate to generate a product t... | Wikipedia/Substrate_(chemistry) |
Garland Science was a publishing group that specialized in developing textbooks in a wide range of life sciences subjects, including cell and molecular biology, immunology, protein chemistry, genetics, and bioinformatics. It was a subsidiary of the Taylor & Francis Group.
== History ==
The firm was founded as Garland... | Wikipedia/Garland_Science |
An intermolecular force (IMF; also secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction
or repulsion which act between atoms and other types of neighbouring particles (e.g. atoms or ions). Intermolecular forces are weak relative to intramolecular ... | Wikipedia/Keesom_force |
After the explanation of van der Waals forces by Fritz London, several scientists soon realised that his definition could be extended from the interaction of two molecules with induced dipoles to macro-scale objects by summing all of the forces between the molecules in each of the bodies involved. The theory is named a... | Wikipedia/Hamaker_theory |
In chemistry, hydration energy (also hydration enthalpy) is the amount of energy released when one mole of ions undergoes solvation. Hydration energy is one component in the quantitative analysis of solvation. It is a particular special case of water. The value of hydration energies is one of the most challenging aspe... | Wikipedia/Hydration_energy |
In differential geometry, the Ricci curvature tensor, named after Gregorio Ricci-Curbastro, is a geometric object which is determined by a choice of Riemannian or pseudo-Riemannian metric on a manifold. It can be considered, broadly, as a measure of the degree to which the geometry of a given metric tensor differs loca... | Wikipedia/Ricci_curvature_tensor |
The covariant formulation of classical electromagnetism refers to ways of writing the laws of classical electromagnetism (in particular, Maxwell's equations and the Lorentz force) in a form that is manifestly invariant under Lorentz transformations, in the formalism of special relativity using rectilinear inertial coor... | Wikipedia/Formulation_of_Maxwell's_equations_in_special_relativity |
Bessel functions, named after Friedrich Bessel who was the first to systematically study them in 1824, are canonical solutions y(x) of Bessel's differential equation
x
2
d
... | Wikipedia/Spherical_Bessel_functions |
Bessel functions, named after Friedrich Bessel who was the first to systematically study them in 1824, are canonical solutions y(x) of Bessel's differential equation
x
2
d
... | Wikipedia/Spherical_Bessel_function |
"On Physical Lines of Force" is a four-part paper written by James Clerk Maxwell, published in 1861. In it, Maxwell derived the equations of electromagnetism in conjunction with a "sea" of "molecular vortices" which he used to model Faraday's lines of force. Maxwell had studied and commented on the field of electricity... | Wikipedia/On_Physical_Lines_of_Force |
The lumped-element model (also called lumped-parameter model, or lumped-component model) is a simplified representation of a physical system or circuit that assumes all components are concentrated at a single point and their behavior can be described by idealized mathematical models. The lumped-element model simplifies... | Wikipedia/Lumped_element_model |
Ferromagnetism is a property of certain materials (such as iron) that results in a significant, observable magnetic permeability, and in many cases, a significant magnetic coercivity, allowing the material to form a permanent magnet. Ferromagnetic materials are noticeably attracted to a magnet, which is a consequence o... | Wikipedia/Ferromagnetic_materials |
A magnetic circuit is made up of one or more closed loop paths containing a magnetic flux. The flux is usually generated by permanent magnets or electromagnets and confined to the path by magnetic cores consisting of ferromagnetic materials like iron, although there may be air gaps or other materials in the path. M... | Wikipedia/Resistance–reluctance_model |
The lumped-element model (also called lumped-parameter model, or lumped-component model) is a simplified representation of a physical system or circuit that assumes all components are concentrated at a single point and their behavior can be described by idealized mathematical models. The lumped-element model simplifies... | Wikipedia/Lumped-element_model |
In general relativity, an electrovacuum solution (electrovacuum) is an exact solution of the Einstein field equation in which the only nongravitational mass–energy present is the field energy of an electromagnetic field, which must satisfy the (curved-spacetime) source-free Maxwell equations appropriate to the given ge... | Wikipedia/Electrovacuum_solution |
In electromagnetism and applications, an inhomogeneous electromagnetic wave equation, or nonhomogeneous electromagnetic wave equation, is one of a set of wave equations describing the propagation of electromagnetic waves generated by nonzero source charges and currents. The source terms in the wave equations make the p... | Wikipedia/Nonhomogeneous_electromagnetic_wave_equation |
In electrical engineering, power conversion is the process of converting electric energy from one form to another.
A power converter is an electrical device for converting electrical energy between alternating current (AC) and direct current (DC). It can also change the voltage or frequency of the current.
Power conver... | Wikipedia/Electric_power_conversion |
The Model V was among the early electromechanical general purpose computers, designed by George Stibitz and built by Bell Telephone Laboratories, operational in 1946.
Only two machines were built: first one was installed at National Advisory Committee for Aeronautics (NACA, later NASA), the second (1947) at the US Army... | Wikipedia/Model_V |
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensi... | Wikipedia/Telegraphy |
Applied Physics Letters is a weekly peer-reviewed scientific journal that is published by the American Institute of Physics. Its focus is rapid publication and dissemination of new experimental and theoretical papers regarding applications of physics in all disciplines of science, engineering, and modern technology. Ad... | Wikipedia/Applied_Physics_Letters |
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