112 relations: Alternating current, American Journal of Physics, Ampere, Arnold Sommerfeld, Atom, Atomic spacing, Barlow's law, Bloch wave, Charge carrier, Classical mechanics, Classical physics, Complex number, Condensed matter physics, Constitutive equation, Coulomb, Coulomb's law, Crystallographic defect, Current density, Current–voltage characteristic, Derivative, Dictionary of Scientific Biography, Differential equation, Direct current, Drift velocity, Drude model, Electric current, Electric field, Electric potential, Electrical breakdown, Electrical conductor, Electrical impedance, Electrical network, Electrical resistance and conductance, Electrical resistivity and conductivity, Electromotive force, Electron, Electronic band structure, Electronic structure, Ensemble average (statistical mechanics), Euler's formula, Felix Bloch, Fermi–Dirac statistics, Fick's laws of diffusion, Flux, Francis Ronalds, Free electron model, Galvanometer, Georg Ohm, Green–Kubo relations, Gustav Kirchhoff, ..., Hagen–Poiseuille equation, Heat, Henry Cavendish, Hydraulic analogy, Insulator, International System of Units, Ion, Isotope, J. J. Thomson, James Clerk Maxwell, Johnson–Nyquist noise, Joseph Fourier, Joule heating, Laminar flow, Leyden jar, Linear time-invariant theory, Litre, Lorentz force, Lorentz transformation, Matter, Maximum power transfer theorem, Maxwell's equations, Momentum, Network analysis (electrical circuits), Norton's theorem, Number density, Ohm, Pascal (unit), Paul Drude, Plasma (physics), Popular Science, Pounds per square inch, Proportionality (mathematics), Quantum mechanics, Resistor, Rest frame, Robert Andrews Millikan, Samuel Morse, Scalar (mathematics), Scattering, Scientific law, Semiconductor, Sheet resistance, Siemens (unit), Sigma, Silicon, Sine wave, Superposition theorem, Temperature, Thévenin's theorem, Thermal conductivity, Thermal energy, Thermocouple, Time-invariant system, Turbulence, Valence and conduction bands, Vector (mathematics and physics), Volt, Voltage, Voltaic pile, Werner von Siemens, Winfield Hill. Expand index (62 more) » « Shrink index
Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction.
The American Journal of Physics is a monthly, peer-reviewed scientific journal published by the American Association of Physics Teachers and the American Institute of Physics.
The ampere (symbol: A), often shortened to "amp",SI supports only the use of symbols and deprecates the use of abbreviations for units.
Arnold Johannes Wilhelm Sommerfeld, (5 December 1868 – 26 April 1951) was a German theoretical physicist who pioneered developments in atomic and quantum physics, and also educated and mentored a large number of students for the new era of theoretical physics.
An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element.
Atomic spacing refers to the distance between the nuclei of atoms in a material.
Barlow's law was an incorrect physical law proposed by Peter Barlow in 1825 to describe the ability of wires to conduct electricity.
A Bloch wave (also called Bloch state or Bloch function or Bloch wavefunction), named after Swiss physicist Felix Bloch, is a type of wavefunction for a particle in a periodically-repeating environment, most commonly an electron in a crystal.
In physics, a charge carrier is a particle free to move, carrying an electric charge, especially the particles that carry electric charges in electrical conductors.
Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.
The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.
Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.
Christmas traditions vary from country to country.
Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars and galaxies.
Classical physics refers to theories of physics that predate modern, more complete, or more widely applicable theories.
A complex number is a number that can be expressed in the form, where and are real numbers, and is a solution of the equation.
Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter.
In physics and engineering, a constitutive equation or constitutive relation is a relation between two physical quantities (especially kinetic quantities as related to kinematic quantities) that is specific to a material or substance, and approximates the response of that material to external stimuli, usually as applied fields or forces.
The coulomb (symbol: C) is the International System of Units (SI) unit of electric charge.
Coulomb's law, or Coulomb's inverse-square law, is a law of physics for quantifying the amount of force with which stationary electrically charged particles repel or attract each other.
Crystalline solids exhibit a periodic crystal structure.
In electromagnetism, current density is the electric current per unit area of cross section.
A current–voltage characteristic or I–V curve (current–voltage curve) is a relationship, typically represented as a chart or graph, between the electric current through a circuit, device, or material, and the corresponding voltage, or potential difference across it.
The derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value).
The Dictionary of Scientific Biography is a scholarly reference work that was published from 1970 through 1980.
A differential equation is a mathematical equation that relates some function with its derivatives.
Direct current (DC) is the unidirectional flow of electric charge.
The drift velocity is the average velocity that a particle, such as an electron, attains in a material due to an electric field.
The Drude model of electrical conduction was proposed in 1900 by Paul Drude to explain the transport properties of electrons in materials (especially metals).
An electric current is a flow of electric charge.
An electric field is a vector field surrounding an electric charge that exerts force on other charges, attracting or repelling them.
An electric potential (also called the electric field potential, potential drop or the electrostatic potential) is the amount of work needed to move a unit positive charge from a reference point to a specific point inside the field without producing any acceleration.
Electrical breakdown or dielectric breakdown is when current flows through an electrical insulator when the voltage applied across it exceeds the breakdown voltage.
In physics and electrical engineering, a conductor is an object or type of material that allows the flow of an electrical current in one or more directions.
Electrical impedance is the measure of the opposition that a circuit presents to a current when a voltage is applied.
An electrical network is an interconnection of electrical components (e.g. batteries, resistors, inductors, capacitors, switches) or a model of such an interconnection, consisting of electrical elements (e.g. voltage sources, current sources, resistances, inductances, capacitances).
The electrical resistance of an electrical conductor is a measure of the difficulty to pass an electric current through that conductor.
Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is a fundamental property that quantifies how strongly a given material opposes the flow of electric current.
Electromotive force, abbreviated emf (denoted \mathcal and measured in volts), is the electrical intensity or "pressure" developed by a source of electrical energy such as a battery or generator.
The electron is a subatomic particle, symbol or, whose electric charge is negative one elementary charge.
In solid-state physics, the electronic band structure (or simply band structure) of a solid describes the range of energies that an electron within the solid may have (called energy bands, allowed bands, or simply bands) and ranges of energy that it may not have (called band gaps or forbidden bands).
In quantum chemistry, electronic structure is the state of motion of electrons in an electrostatic field created by stationary nuclei.
In statistical mechanics, the ensemble average is defined as the mean of a quantity that is a function of the microstate of a system (the ensemble of possible states), according to the distribution of the system on its micro-states in this ensemble.
Euler's formula, named after Leonhard Euler, is a mathematical formula in complex analysis that establishes the fundamental relationship between the trigonometric functions and the complex exponential function.
Felix Bloch (23 October 1905 – 10 September 1983) was a Swiss physicist, working mainly in the U.S. He and Edward Mills Purcell were awarded the 1952 Nobel Prize for Physics for "their development of new ways and methods for nuclear magnetic precision measurements."Sohlman, M (Ed.) Nobel Foundation directory 2003. Vastervik, Sweden: AB CO Ekblad; 2003.
In quantum statistics, a branch of physics, Fermi–Dirac statistics describe a distribution of particles over energy states in systems consisting of many identical particles that obey the Pauli exclusion principle.
Fick's laws of diffusion describe diffusion and were derived by Adolf Fick in 1855.
Flux describes the quantity which passes through a surface or substance.
Sir Francis Ronalds FRS (21 February 1788 – 8 August 1873) was an English scientist and inventor, and arguably the first electrical engineer.
In solid-state physics, the free electron model is a simple model for the behaviour of charge carriers in a metallic solid.
A galvanometer is an electromechanical instrument used for detecting and indicating electric current.
Georg Simon Ohm (16 March 1789 – 6 July 1854) was a German physicist and mathematician.
The Green–Kubo relations (Melville S. Green 1954, Ryogo Kubo 1957) give the exact mathematical expression for transport coefficients \gamma in terms of integrals of time correlation functions.
Gustav Robert Kirchhoff (12 March 1824 – 17 October 1887) was a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects.
In nonideal fluid dynamics, the Hagen–Poiseuille equation, also known as the Hagen–Poiseuille law, Poiseuille law or Poiseuille equation, is a physical law that gives the pressure drop in an incompressible and Newtonian fluid in laminar flow flowing through a long cylindrical pipe of constant cross section.
In thermodynamics, heat is energy transferred from one system to another as a result of thermal interactions.
Henry Cavendish FRS (10 October 1731 – 24 February 1810) was a British natural philosopher, scientist, and an important experimental and theoretical chemist and physicist.
The electronic–hydraulic analogy (derisively referred to as the drain-pipe theory by Oliver Lodge) is the most widely used analogy for "electron fluid" in a metal conductor.
Insulator may refer to.
The International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement.
An ion is an atom or molecule that has a non-zero net electrical charge (its total number of electrons is not equal to its total number of protons).
Isotopes are variants of a particular chemical element which differ in neutron number.
Sir Joseph John Thomson (18 December 1856 – 30 August 1940) was an English physicist and Nobel Laureate in Physics, credited with the discovery and identification of the electron; and with the discovery of the first subatomic particle.
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish scientist in the field of mathematical physics.
Johnson–Nyquist noise (thermal noise, Johnson noise, or Nyquist noise) is the electronic noise generated by the thermal agitation of the charge carriers (usually the electrons) inside an electrical conductor at equilibrium, which happens regardless of any applied voltage.
Jean-Baptiste Joseph Fourier (21 March 1768 – 16 May 1830) was a French mathematician and physicist born in Auxerre and best known for initiating the investigation of Fourier series and their applications to problems of heat transfer and vibrations.
Joule heating, also known as Ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor produces heat.
In fluid dynamics, laminar flow (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption between the layers.
A Leyden jar (or Leiden jar) stores a high-voltage electric charge (from an external source) between electrical conductors on the inside and outside of a glass jar.
Linear time-invariant theory, commonly known as LTI system theory, comes from applied mathematics and has direct applications in NMR spectroscopy, seismology, circuits, signal processing, control theory, and other technical areas.
The litre (SI spelling) or liter (American spelling) (symbols L or l, sometimes abbreviated ltr) is an SI accepted metric system unit of volume equal to 1 cubic decimetre (dm3), 1,000 cubic centimetres (cm3) or 1/1,000 cubic metre. A cubic decimetre (or litre) occupies a volume of 10 cm×10 cm×10 cm (see figure) and is thus equal to one-thousandth of a cubic metre. The original French metric system used the litre as a base unit. The word litre is derived from an older French unit, the litron, whose name came from Greek — where it was a unit of weight, not volume — via Latin, and which equalled approximately 0.831 litres. The litre was also used in several subsequent versions of the metric system and is accepted for use with the SI,, p. 124. ("Days" and "hours" are examples of other non-SI units that SI accepts.) although not an SI unit — the SI unit of volume is the cubic metre (m3). The spelling used by the International Bureau of Weights and Measures is "litre", a spelling which is shared by almost all English-speaking countries. The spelling "liter" is predominantly used in American English. One litre of liquid water has a mass of almost exactly one kilogram, because the kilogram was originally defined in 1795 as the mass of one cubic decimetre of water at the temperature of melting ice. Subsequent redefinitions of the metre and kilogram mean that this relationship is no longer exact.
In physics (particularly in electromagnetism) the Lorentz force is the combination of electric and magnetic force on a point charge due to electromagnetic fields.
In physics, the Lorentz transformations (or transformation) are coordinate transformations between two coordinate frames that move at constant velocity relative to each other.
In the classical physics observed in everyday life, matter is any substance that has mass and takes up space by having volume.
In electrical engineering, the maximum power transfer theorem states that, to obtain maximum external power from a source with a finite internal resistance, the resistance of the load must equal the resistance of the source as viewed from its output terminals.
Maxwell's equations are a set of partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits.
In Newtonian mechanics, linear momentum, translational momentum, or simply momentum (pl. momenta) is the product of the mass and velocity of an object.
A network, in the context of electronics, is a collection of interconnected components.
New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.
New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.
In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.
Known in Europe as the Mayer–Norton theorem, Norton's theorem holds, to illustrate in DC circuit theory terms (see that image).
In physics, astronomy, chemistry, biology and geography, number density (symbol: n or ρN) is an intensive quantity used to describe the degree of concentration of countable objects (particles, molecules, phonons, cells, galaxies, etc.) in physical space: three-dimensional volumetric number density, two-dimensional areal number density, or one-dimensional line number density.
The ohm (symbol: Ω) is the SI derived unit of electrical resistance, named after German physicist Georg Simon Ohm.
The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength.
Paul Karl Ludwig Drude (12 July 1863 – 5 July 1906) was a German physicist specializing in optics.
Plasma (Henry George Liddell, Robert Scott, A Greek English Lexicon, on Perseus) is one of the four fundamental states of matter, and was first described by chemist Irving Langmuir in the 1920s.
Popular Science (also known as PopSci) is an American quarterly magazine carrying popular science content, which refers to articles for the general reader on science and technology subjects.
The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in2; abbreviation: psi) is a unit of pressure or of stress based on avoirdupois units.
In mathematics, two variables are proportional if there is always a constant ratio between them.
Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element.
In special relativity the rest frame of a particle is the coordinate system (frame of reference) in which the particle is at rest.
Robert Andrews Millikan (March 22, 1868 – December 19, 1953) was an American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the elementary electronic charge and for his work on the photoelectric effect.
Samuel Finley Breese Morse (April 27, 1791 – April 2, 1872) was an American painter and inventor. After having established his reputation as a portrait painter, in his middle age Morse contributed to the invention of a single-wire telegraph system based on European telegraphs. He was a co-developer of the Morse code and helped to develop the commercial use of telegraphy.
A scalar is an element of a field which is used to define a vector space.
Scattering is a general physical process where some forms of radiation, such as light, sound, or moving particles, are forced to deviate from a straight trajectory by one or more paths due to localized non-uniformities in the medium through which they pass.
A scientific law is a statement based on repeated experimental observations that describes some aspect of the universe.
A semiconductor material has an electrical conductivity value falling between that of a conductor – such as copper, gold etc.
Sheet resistance is a measure of resistance of thin films that are nominally uniform in thickness.
The siemens (symbol: S) is the derived unit of electric conductance, electric susceptance and electric admittance in the International System of Units (SI).
Sigma (upper-case Σ, lower-case σ, lower-case in word-final position ς; σίγμα) is the eighteenth letter of the Greek alphabet.
Silicon is a chemical element with symbol Si and atomic number 14.
A sine wave or sinusoid is a mathematical curve that describes a smooth periodic oscillation.
The superposition theorem for electrical circuits states that for a linear system the response (voltage or current) in any branch of a bilateral linear circuit having more than one independent source equals the algebraic sum of the responses caused by each independent source acting alone, where all the other independent sources are replaced by their internal impedances.
Temperature is a physical quantity expressing hot and cold.
As originally stated in terms of DC resistive circuits only, Thévenin's theorem holds that: In circuit theory terms, the theorem allows any one-port network to be reduced to a single voltage source and a single impedance.
Thermal conductivity (often denoted k, λ, or κ) is the property of a material to conduct heat.
Thermal energy is a term used loosely as a synonym for more rigorously-defined thermodynamic quantities such as the internal energy of a system; heat or sensible heat, which are defined as types of transfer of energy (as is work); or for the characteristic energy of a degree of freedom in a thermal system kT, where T is temperature and k is the Boltzmann constant.
A thermocouple is an electrical device consisting of two dissimilar electrical conductors forming electrical junctions at differing temperatures.
A time-invariant (TIV) system has a time-dependent system function that is not a direct function of time.
In fluid dynamics, turbulence or turbulent flow is any pattern of fluid motion characterized by chaotic changes in pressure and flow velocity.
In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level and thus determine the electrical conductivity of the solid.
When used without any further description, vector usually refers either to.
The volt (symbol: V) is the derived unit for electric potential, electric potential difference (voltage), and electromotive force.
Voltage, electric potential difference, electric pressure or electric tension (formally denoted or, but more often simply as V or U, for instance in the context of Ohm's or Kirchhoff's circuit laws) is the difference in electric potential between two points.
The voltaic pile was the first electrical battery that could continuously provide an electric current to a circuit.
Ernst Werner Siemens (von Siemens from 1888;; 13 December 1816 – 6 December 1892) was a German inventor and industrialist.
Winfield Hill is the Director of the Electronics Engineering Laboratory at the Rowland Institute at Harvard University.
2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.
2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.