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This '''glossary of electrical and electronics engineering''' is a list of definitions of terms and concepts related specifically to [[electrical engineering]] and [[electronics engineering]]. For terms related to engineering in general, see [[Glossary of engineering]].
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==A==
{{glossary}}
{{term|
{{defn| {{term|
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{{defn| {{term|[[Rectifier|AC-to-DC conversion (rectifier)]]}}
{{defn|Rectification of AC current, so that current flows in only one direction.}}
{{term|[[AC-to-AC converter]]}}
{{defn|A power converter where the input and output are both {{gli|alternating current}}, but may differ in frequency or other characteristics.}}
{{term|[[AC/DC receiver design]]}}
{{defn|A radio receiver that can operate from either {{gli|alternating current}} or {{gli|direct current}} wall socket power.}}
{{term|[[active rectification]]}}
{{defn|A circuit where rectifier devices are externally controlled to change AC to current flowing in one direction.}}
{{term|[[actuator]]}}
{{defn|An end device of a control system, that manipulates a physical variable such as a valve opening or position of a machine part.}}
{{term|[[adaptive control]]}}
{{defn|A control strategy where parameters are adjusted as the controlled process changes.}}
{{term|[[additive white Gaussian noise]]}}
{{defn|A noise model that is used in telecommunications to model the effects of various random processes.}}
{{term|[[adjustable-speed drive]]}}
{{defn|Control for a motor that allows more than one speed to be selected.}}
{{term|[[advanced z-transform]]}}
{{defn|A mathematical technique used to model and analyze digital systems.}}
{{term|[[affinity laws]]}}
{{defn|Mathematical formulas that relate the speed, flow, and diameter of pumps, fans, blowers, and turbines, useful for predicting output under varying conditions.}}
{{term|agbioeletric}}
{{defn|A brand name of a kind of vegetable oil for use in transformers.}}
{{term|[[American Institute of Electrical Engineers|AIEE]]}}
{{defn|American Institute of Electrical Engineers, predecessor organization to IEEE.}}
{{term|[[alpha–beta transformation]]}}
{{defn|A mathematical technique useful in analysis of three-phase circuits.}}
{{term|[[alternating current]]}}
{{defn|Electric current that reverses direction periodically.}}
{{term|[[alternator]]}}
{{defn|An electrical machine that converts mechanical power into AC electric power.}}
{{term|[[alternator synchronization]]}}
{{defn|The process of synchronizing an alternator to a grid or another alternator.}}
{{term|[[aluminium smelting]]}}
{{defn|Reduction of aluminium ore to metal, by use of large amounts of electric power.}}
{{term|[[ammeter]]}}
{{defn|An instrument that measures electric current.}}
{{term|[[amorphous metal transformer]]}}
{{defn|A power transformer where the metallic core is made of metals cooled so quickly that they do not form a crystal structure; such transformers can reduce some kinds of energy loss.}}
{{term|[[ampacity]]}}
{{
{{term|[[ampere]]}}
{{defn|The [[International System of Units|SI]] unit of electrical current.}}
{{term|[[Ampère's circuital law]]}}
{{defn|The mathematical relation between the integral of the magnetic field over some closed curve to the {{gli|current}} passing through the region bound by the curve.}}
{{term|[[Ampère's force law]]}}
{{defn|The mathematical relation between the force between two {{gli|current}} carrying conductors and the current flowing in them.}}
{{term|[[Ampère's law]]}}
{{defn|Ampère's circuital law.}}
{{term|[[amplidyne]]}}
{{defn|An electric machine that allows a small {{gli|current}} to control a much larger current.}}
{{term|[[amplifier]]}}
{{defn|A system that produces an output that replicates an input signal but with a larger magnitude.}}
{{term|[[amplitude modulation]]}}
{{defn|Transmission of information by changing the magnitude of a carrier signal, for example sending sound by radio.}}
{{term|[[analog circuit]]}}
{{defn|A circuit where currents and voltages vary continually within some practical range, in proportion to some signal.}}
{{term|[[analog filter]]}}
{{defn|An analog circuit that alters some frequency-related property of a signal.}}
{{term|[[analog signal processing]]}}
{{defn|Generally, techniques used to alter signals that rely on voltages or currents that vary continually over a practical range.}}
{{term|[[analog signal]]}}
{{defn|A signal whose properties ({{gli|current}}, {{gli|voltage}}) vary proportionally to the information transmitted.}}
{{term|[[analog-to-digital converter]]}}
{{defn|A circuit that produces a number proportional to the magnitude of a {{gli|voltage}} or {{gli|current}}.}}
{{term|[[anode]]}}
{{defn|The terminal of an electrochemical or electronic device through which conventional {{gli|current}} flows inward.}}
{{term|[[antenna (radio)|antenna]]}}
{{defn|A structure which converts between electromagnetic waves in space and currents in a conductor.}}
{{term|[[apparent power]]}}
{{defn|In an {{gli|alternating current}} power circuit, the product of the magnitude of RMS {{gli|voltage}} and {{gli|current}}.}}
{{term|[[Apple Inc.]] (formerly known as Apple Computer)}}
{{defn|A company that makes mobile telephones and computers.}}
{{term|[[arbitrary waveform generator]]}}
{{defn|A type of signal generator that can generate almost any waveform.}}
{{term|[[arc converter]]}}
{{defn|A device once used to generate radio waves.}}
{{term|[[arc furnace]]}}
{{defn|A furnace that melts material by use of an electric arc.}}
{{term|[[arc lamp]]}}
{{defn|An electric lamp that generates light from an electric arc.}}
{{term|[[arc welder]]}}
{{defn|A device used to join metals by melting them with an electric arc.}}
{{term|[[armature (electrical engineering)|armature]]}}
{{defn|That part of an electrical machine that converts electrical energy to mechanical energy (or vice versa).}}
{{term|[[artificial intelligence]]}}
{{defn|A computer system that replicates some feature of human intelligence.}}
{{term|[[artificial neural network]]}}
{{defn|A network of individual logic elements in multiple layers that mimics the function of a biological nervous system; a technique in artificial intelligence.}}
{{term|[[asymptotic stability]]}}
{{defn|A condition of a control system where the output eventually reaches a steady-state value in response to any input.}}
{{term|[[asynchronous circuit]]}}
{{defn|A digital circuit where states propagate through a circuit without a synchronizing clock impulse.}}
{{term|[[audio and video connector]]}}
{{defn|An electrical fitting used to connect cables carrying audio or video signals.}}
{{term|[[audio equipment]]}}
{{defn|Equipment used to handle signals at frequencies within the human range of hearing.}}
{{term|[[audio filter]]}}
{{defn|A circuit intended to alter some frequency-related property of a signal carrying sound information.}}
{{term|[[audio frequency]]}}
{{defn|A signal whose frequency is within the range of human hearing.}}
{{term|[[audio noise reduction]]}}
{{defn|Reduction of interfering signals in an audio signal.}}
{{term|[[audio signal processing]]}}
{{defn|Alteration of any properties of a signal carrying sound information (dynamic range, frequency response, or others).}}
{{term|[[audion tube]]}}
{{defn|An early three electrode vacuum tube that had amplifying properties.}}
{{term|[[Austin transformer]]}}
{{defn|A kind of isolation transformer.}}
{{term|[[automatic gain control]]}}
{{defn|A circuit that automatically adjusts the magnitude of a signal to prevent it from becoming too small or too large.}}
{{term|[[automatic transfer switch]]}}
{{defn|An electrical switch used to automatically select a standby source of electrical power when the principal source is lost.}}
{{term|[[automation]]}}
{{defn|Automatic control of a process.}}
{{term|[[autorecloser]]}}
{{defn|A circuit protection device for overhead power distribution lines which briefly interrupts a circuit when a fault is detected, then restores the circuit in the expectation the fault has cleared.}}
{{term|[[autotransformer]]}}
{{defn|A transformer where the primary and secondary circuits share some of the transformer windings.}}
{{term|[[availability factor]]}}
{{defn|The fraction of time that a power plant is available to produce power.}}
{{term|[[avalanche diode]]}}
{{defn|A diode intended for regular operation in the reverse, avalanche breakdown, mode. Used as a {{gli|voltage}} reference, noise source, and in certain classes of microwave oscillator device.}}
{{term|[[average rectified value]]}}
{{defn|The average value of an {{gli|alternating current}} waveform, taking the absolute value of the waveform. The average value is generally different from the root-mean-square value.}}
{{glossary end}}
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==B==
{{glossary}}
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{{defn| {{term|[[biasing]]}}
{{defn|The practice of setting the quiescent operating conditions of an amplifying device to obtain desired response.}}
{{term|[[BIBO stability]]}}
{{defn|A control system that produces finite outputs for any finite input.}}
{{term|[[bilinear transform]]}}
{{defn|A mathematical technique to obtain the parameters for a digital filter to duplicate the response of some analog filter transfer function.}}
{{term|[[bimetallic strip]]}}
{{defn|A temperature sensing element made of two metals that have different coefficients of expansion intimately bonded together.}}
{{term|[[Biot–Savart law]]}}
{{defn|The mathematical relationship between a magnetic field and the current producing that field.}}
{{term|[[bipolar junction transistor]]}}
{{defn|A type of transistor with two kinds of charge carriers.}}
{{term|[[blocked rotor test]]}}
{{defn|A test of an electric machine where the machine is energized but the shaft is prevented from turning.}}
{{term|[[Blu-ray]]}}
{{defn|A type of optical disc written and read using a blue/violet laser.}}
{{term|[[Bode plot]]}}
{{defn|A plot of the amplitude and phase frequency response of a system, where the actual response is approximated by straight line segments.}}
{{term|[[Boolean algebra (logic)]]}}
{{defn|A type of algebra that deals with values that can only hold values "true" and "false", of great use in design and analysis of digital systems.}}
{{term|[[boost converter]]}}
{{defn|Any power converter circuit that can produce an output {{gli|voltage}} larger than its input voltage.}}
{{term|[[booster (electric power)|booster]]}}
{{defn|A device used to increase voltage on an electric power distribution system, such as a motor-generator set on a DC system.}}
{{term|[[bound charge]]}}
{{defn|Electric charge in a material that is not free to move through the material.}}
{{term|[[braking chopper]]}}
{{defn|A device used to absorb energy from a motor to slow it down.}}
{{term|[[branch circuit]]}}
{{defn|In building wiring, any circuit from the main panelboard to utilization equipment or receptacles.}}
{{term|[[breakdown voltage]]}}
{{defn|The maximum {{gli|voltage}} a device can withstand without damage.}}
{{term|[[bridge rectifier]]}}
{{defn|A set of rectifier diodes used to convert {{gli|alternating current}} to {{gli|direct current}}.}}
{{term|[[broadcasting]]}}
{{defn|Transmission of a signal to many receivers.}}
{{term|[[brush (electric)|brush]]}}
{{defn|A sliding electrical contact between a moving part and a stationary part.}}
{{term|[[brushed DC electric motor]]}}
{{defn|An electric motor with brushes.}}
{{term|[[brushless DC electric motor]]}}
{{defn|An electric motor without brushes.}}
{{term|[[Buchholz relay]]}}
{{defn|A gas pressure sensing device for protection of oil-filled transformers.}}
{{term|[[Buck converter]]}}
{{defn|Any power converter circuit that produces an output {{gli|voltage}} less than its input voltage.}}
{{term|[[Buck–boost converter]]}}
{{defn|Any power converter circuit that can provide a voltage greater or less than its input voltage.}}
{{term|[[Buck–boost transformer]]}}
{{defn|A transformer that can be used to adjust voltage.}}
{{term|[[busbar]]}}
{{defn|A set of conductors used to distribute current to many branches.}}
{{term|[[bushing (electrical)|bushing]]}}
{{defn|An electrical fitting used to connect external conductors to the interior of apparatus.}}
{{term|[[Butterworth filter]]}}
{{defn|A type of filter with the flattest possible pass band.}}
{{term|[[buzzer]]}}
{{defn|An electromechanical or electronic device that produces a sound when energized.}}
{{glossary end}}
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==C==
{{glossary}}
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{{defn| {{term|[[catenary]]}}
{{defn|A geometric form of curve, the shape of a uniform cable hanging between two supports.}}
{{term|[[cathode ray oscilloscope]]}}
{{defn|An electronic instrument that displays the wave shape of electrical signals on a cathode ray tube.}}
{{term|[[cathode ray tube]]}}
{{defn|A vacuum tube that relies on an electron beam{{Snd}} usually used to render images on a fluorescent screen such as in television sets.}}
{{term|[[cathode]]}}
{{defn|The terminal of an electrochemical or electronic device from which conventional current exits the device.}}
{{term|[[cat's-whisker detector]]}}
{{defn|A radio detector that uses a manually-set "whisker" contact to a crystal of galena or other material, to form a rectifying junction.}}
{{term|[[CATV]]}}
{{defn|Cable television, distribution of television programming over a wire instead of by radio broadcast.}}
{{term|[[cavity magnetron]]}}
{{defn|A vacuum tube that is a high power microwave oscillator, using a resonant cavity and electrons traveling through a magnetic field.}}
{{term|[[CD]]}}
{{defn|A "Compact Disc" used to store digital data or digitally recorded sound using an infrared laser.}}
{{term|[[center tap]]}}
{{defn|A connection on a transformer which has equal voltage to either end of the transformer winding.}}
{{term|[[ceramic resonator]]}}
{{defn|A piezoelectric element used to stabilize the frequency of an oscillator.}}
{{term|[[channel (communications)|channel]]}}
{{defn|Any communication path between a signal transmitter and a signal receiver, or, a pre-selected operating frequency for a radio system.}}
{{term|[[channel capacity]]}}
{{defn|An upper bound on the rate at which information can be reliably transmitted over a communication channel.}}
{{term|[[charactron]]}}
{{defn|A kind of text display vacuum tube that used an internal element to shape an electron beam to represent the shape of letters and other symbols.}}
{{term|[[charge pump]]}}
{{defn|A DC to DC converter circuit that uses capacitors to store energy between stages.}}
{{term|[[charge transfer switch]]}}
{{defn|A kind of charge pump circuit.}}
{{term|[[charge-coupled device]]}}
{{defn|An imaging sensor or data storage device that represents a signal, or pixel, by the charge stored in a capacitor and is able to move that charge from one capacitor to the next.}}
{{term|[[Chebyshev filter]]}}
{{defn|A form of filter that has a steep frequency selective characteristic.}}
{{term|[[choke (electronics)|choke]]}}
{{defn|An induction coil used to block {{gli|alternating current}} and pass {{gli|direct current}}, or to block high frequencies and pass lower frequencies.}}
{{term|[[chopper (electronics)|chopper]]}}
{{defn|A circuit that switches on and off at a high rate, used either for power conversion or to convert a DC signal to a more easily processed AC signal.}}
{{term|[[circle diagram]]}}
{{defn|A representation of the {{gli|voltage}} and {{gli|current}} characteristics of an electrical machine; the plot traces out a circle or part of a circle.}}
{{term|[[circuit breaker panel]]}}
{{defn|A distribution board for electric power that uses circuit breakers as protective elements.}}
{{term|[[circuit breaker]]}}
{{defn|An automatically operated electrical switch that opens to interrupt a short circuit or other fault.}}
{{term|[[circuit theory]]}}
{{defn|The mathematical theory of electrical circuits.}}
{{term|[[Circuit Total Limitation]] (CTL)}}
{{defn|A US National Electrical Code rule for the number of circuits in a panel board.}}
{{term|[[clamp meter]]}}
{{defn|An ammeter that measures current with a split core that can be clamped on a wire.}}
{{term|[[Clapp oscillator]]}}
{{defn|An electronic oscillator circuit that uses three capacitors and an inductor.}}
{{term|[[class of accuracy in electrical measurements]]}}
{{defn|A measure of the error produced by an electrical measuring instrument.}}
{{term|[[closed-loop controller]]}}
{{defn|Any controller that manipulates some process variable to minimize the difference between the current state of the variable and the desired set point, such as temperature, flow, or others.}}
{{term|[[CMOS]]}}
{{defn|Complementary metal–oxide–semiconductor, a fabrication process for MOSFETs and integrated circuits}}
{{term|[[coaxial cable]]}}
{{defn|A cable with an inner conductor centered inside a flexible tubular conductor, used for radio frequency transmission lines.}}
{{term|[[Cockcroft–Walton generator]]}}
{{defn|A kind of circuit for generating very high DC voltage.}}
{{term|[[cogeneration]]}}
{{defn|Production of electricity along with some other desired product, such as process steam or desalinated water.}}
{{term|[[cold cathode]]}}
{{defn|An element of a vacuum tube that emits electrons without a heating circuit.}}
{{term|[[Colossus (computer)|Colossus]]}}
{{defn|A British code breaking system used during World War II.}}
{{term|[[combined cycle]]}}
{{defn|A thermal power plant that improves efficiency with two different kinds of energy extraction from the combustion products gas stream, such as a gas turbine followed by a steam boiler.}}
{{term|[[communication system]]}}
{{defn|A system intended to convey information from one place to another with an expected degree of performance.}}
{{term|[[communications satellite]]}}
{{defn|A satellite in Earth orbit designed for international telephone, television, or data transmission.}}
{{term|[[commutation cell]]}}
{{defn|The elementary switching device in a power converter circuit; it could be a transistor, a {{gli|thyristor}}, a mercury-arc valve, or others.}}
{{term|[[commutator (electric)|commutator]]}}
{{defn|A component of a DC electric machine that connects the rotating coils with an external circuit through brushes.}}
{{term|[[compact fluorescent lamp]]}}
{{defn|A fluorescent lamp with a folded or spiral tube, designed to fit in the same space as an incandescent lamp of similar light output.}}
{{term|[[Compactron]]}}
{{defn|A brand of vacuum tube, used in some radio and television sets, that combined multiple independent functions in one envelope.}}
{{term|[[compensation winding]]}}
{{defn|A winding on a motor or generator to improve commutation at heavy load.}}
{{term|[[computed tomography]]}}
{{defn|Production of images of a cross-section through an object by multiple X-ray measurements processed in a computer.}}
{{term|[[computer engineering]]}}
{{defn|The profession of designing computers.}}
{{term|[[computer hardware]]}}
{{defn|That part of a computer system with physical existence.}}
{{term|[[computer programming]]}}
{{defn|The practice of producing instructions for a computer to achieve some desired effect.}}
{{term|[[computer-aided design]] (CAD)}}
{{defn|A design discipline where a computer is used to produce graphical representation of the design or to assist in calculating performance parameters.}}
{{term|[[conduction band]]}}
{{defn|In a conductor, the energy levels of charge carriers that are free to move through the material.}}
{{term|[[constant k filter]]}}
{{defn|A method formerly used for designing filters for a required characteristic.}}
{{term|[[consumer electronics]]}}
{{defn|Electronic devices intended to be owned by consumers directly; a mobile cell phone is "consumer electronics" but the cell site it communicates with is not.}}
{{term|[[contactor]]}}
{{defn|An automatically controlled electrical switch (relay), used to operate motors or other high-current loads.}}
{{term|[[continuous Fourier transform]]}}
{{defn|A mathematical operation that expresses a signal in time as the sum of its frequency components.}}
{{term|[[continuous signal]]}}
{{defn|A signal that can take any value within its range.}}
{{term|[[control engineering]]}}
{{defn|The application of control theory to practical problems.}}
{{term|[[control system]]}}
{{defn|The equipment used to adjust some parameter of an ongoing process to regulate its behavior to a desired goal, such as positioning a disk drive head or regulating temperature of a furnace.}}
{{term|[[control theory]]}}
{{defn|The mathematical study of behavior of control systems.}}
{{term|[[controllability]]}}
{{defn|In control theory, the degree to which a system can be put into any desired state given manipulation of one variable.}}
{{term|[[controller (control theory)|controller]]}}
{{defn|A system that adjusts some variable to control a process.}}
{{term|[[copper cable certification]]}}
{{defn|The process of testing a computer network cable installation to verify that it meets standards.}}
{{term|[[copper loss]]}}
{{defn|That portion of an electric machine or transformer's loss attributed to the resistance of conductors (which are not necessarily made of copper).}}
{{term|[[corona ring]]}}
{{defn|A component of a high-voltage system intended to smooth out the electric field distribution around energized parts.}}
{{term|[[coulomb]]}}
{{defn|The [[International System of Units|SI]] unit of electric charge.}}
{{term|[[Coulomb's law]]}}
{{defn|The mathematical relation between force, electric charge and distance.}}
{{term|[[CPU]]}}
{{defn|Central Processing Unit, the element of a computer that carries out arithmetic and logic operations.}}
{{term|[[crest factor]]}}
{{defn|The ratio of peak to effective (RMS) value of a waveform.}}
{{term|[[crossed-field amplifier]]}}
{{defn|A type of microwave amplifier vacuum tube.}}
{{term|[[crosstalk]]}}
{{defn|Objectionable presence of a signal from one circuit in another circuit sharing the same transmission path, such as a cable.}}
{{term|[[crystal oscillator]]}}
{{defn|An electronic oscillator whose frequency is stabilized by a piezoelectric crystal resonator element.}}
{{term|[[Ćuk converter]]}}
{{defn|One kind of buck-boost voltage converter that uses a capacitor as an energy storage element.}}
{{term|[[current (electricity)|current]]}}
{{defn|The movement of electric charge.}}
{{term|[[current density]]}}
{{defn|The current flowing per unit area of a conductor.}}
{{term|[[current source inverter]]}}
{{defn|A type of power inverter where an inductor tends to keep a constant current flowing in the inverter stage.}}
{{term|[[current source]]}}
{{defn|In circuit theory, an element that produces a defined current independent of the connected circuit properties.}}
{{term|[[current transformer]]}}
{{defn|An instrument transformer used for measuring current in AC power systems.}}
{{term|[[current-to-voltage converter]]}}
{{defn|A {{gli|transducer}} that produces an output {{gli|voltage}} in response to an input {{gli|current}}.}}
{{term|[[cybernetics]]}}
{{defn|The science of automatic control systems.}}
{{term|[[cycloconverter]]}}
{{defn|A type of variable-frequency power converter that does not first convert {{gli|alternating current|AC}} to {{gli|direct current|DC}}.}}
{{glossary end}}
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==D==
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{{defn| {{term|[[degaussing]]}}
{{defn|The process of reducing the residual magnetic field in a metallic object, such as a ship.}}
{{term|delay line}}
{{defn|A circuit component that introduces a delay in a signal.}}
{{term|[[delta-wye transformer]]}}
{{defn|One type of connection of a three-phase transformer.}}
{{term|[[demand factor]]}}
{{defn|The fraction of actual use of some quantity, related to the maximum that could be used in a specified time.}}
{{term|[[demand response]]}}
{{defn|The ability of a generating station or grid to follow changes in load while maintaining {{gli|voltage}} and frequency within acceptable limits.}}
{{term|[[demodulation]]}}
{{defn|The process of recovery of information (sound, video, data) from a modulated carrier.}}
{{term|[[describing function]]}}
{{defn|A method for analyzing non-linear control systems.}}
{{term|[[detector (radio)|detector]]}}
{{defn|A circuit that demodulates a radio signal to recover information.}}
{{term|[[DIAC]]}}
{{defn|A four-layer semiconductor diode that has a predictable breakdown characteristic.}}
{{term|[[dielectric]]}}
{{defn|A material that does not allow free flow of electric current.}}
{{term|[[digital audio broadcasting]]}}
{{defn|Transmission of sound by digital signals over radio.}}
{{term|[[digital circuit]]}}
{{defn|A circuit where all points on the signal path have only one of two states.}}
{{term|[[digital computers]]}}
{{defn|A computer made of digital circuits.}}
{{term|[[digital control]]}}
{{defn|A control system that processes signals in digital form.}}
{{term|[[digital filter]]}}
{{defn|A filter implemented as a digital circuit.}}
{{term|[[digital image processing]]}}
{{defn|Manipulation of an image by a digital computer.}}
{{term|[[digital micromirror device]]}}
{{defn|An element of a kind of digital projector system.}}
{{term|[[digital protective relay]]}}
{{defn|A power system protection device that processes signals in digital form.}}
{{term|[[digital signal controller]]}}
{{defn|A type of microprocessor that combines a digital signal processor element with a more general purpose microcontroller.}}
{{term|[[digital signal processing]]}}
{{defn|The technique of modifying the properties of a signal that has been converted to digital form.}}
{{term|[[digital television]]}}
{{defn|Transmission of images using digital techniques.}}
{{term|[[digital-to-analog converter]]}}
{{defn|A device that produces a {{gli|voltage}} or {{gli|current}} that is proportional to a digital value sent to it.}}
{{term|[[diode bridge]]}}
{{defn|An interconnection of diodes to rectify {{gli|alternating current}} to {{gli|direct current}}.}}
{{term|[[diode]]}}
{{defn|A two-terminal passive circuit element, with a preferred direction of current flow.}}
{{term|[[dipole antenna]]}}
{{defn|A simple form of antenna that consists of two conductors oriented end-to-end with a feed in between them.}}
{{anchor|direct current}}{{term|[[direct current]] (DC)}}
{{defn|Electric current that flows in one direction only.}}
{{term|[[direct on line starter]]}}
{{defn|A kind of motor starter that does not reduce the {{gli|voltage}} at the motor terminals.}}
{{term|[[direct torque control]]}}
{{defn|A method of estimating motor torque as part of a variable speed motor drive.}}
{{term|[[discrete cosine transform]]}}
{{defn|A mathematical technique for representing a sampled signal as a sum of cosine waves of different frequencies.}}
{{term|[[discrete Fourier transform]]}}
{{defn|A mathematical technique for representing a sampled signal as a sum of sine and cosine waves of different frequencies.}}
{{term|[[discrete-time signal]]}}
{{defn|A signal represented as a time series of samples taken at regular intervals.}}
{{term|[[displacement current]]}}
{{defn|The effect of a time-varying electric field, which induces a magnetic field just as the motion of electrical charges does.}}
{{term|[[display device]]}}
{{defn|Any device that displays data from an information system, such as a watch readout or an automatic scoreboard.}}
{{term|[[dissipation]]}}
{{defn|The loss of energy in a system, such as dielectric loss in a capacitor.}}
{{term|[[dissolved gas analysis]]}}
{{defn|A technique for fault detection in oil-filled transformers.}}
{{term|[[distributed control system]]}}
{{defn|A control system in which significant parts of the control process are decentralized.}}
{{term|[[distributed-element model]]}}
{{defn|An analysis of an electric circuit where capacitance, inductance, and resistance are distributed along the circuit, as in a transmission line, not concentrated in lumped components.}}
{{term|[[distributed generation]]}}
{{defn|An electrical grid where multiple small sources contribute energy, instead of relatively few large central generating stations.}}
{{term|[[distribution board]]}}
{{defn|A piece of electrical switchgear which distributes electric power to multiple branch circuits.}}
{{term|[[distribution transformer]]}}
{{defn|A power transformer, usually used to change the utility distribution voltage to a lower voltage for use on the customer premises.}}
{{term|[[Dolby]]}}
{{defn|A trademark for a noise reduction technique for analog sound recordings.}}
{{term|[[dot convention]]}}
{{defn|A system for marking terminals on instrument transformers to maintain correct polarity.}}
{{term|[[doubly fed electric machine]]}}
{{defn|An electric machine where both moving and stationary elements have external connections handling significant power.}}
{{term|[[downsampling]]}}
{{defn|A technique for reducing the number of signal samples processed by a digital system; decimation.}}
{{term|[[Dqo transformation]]}}
{{defn|A technique used to simplify mathematical analysis of polyphase electric circuits.}}
{{term|[[droop speed control]]}}
{{defn|A method of regulating generators so that multiple units share the load proportional to their ratings.}}
{{term|[[dual control theory]]}}
{{defn|A branch of control theory that deals with systems whose characteristics are initially unknown.}}
{{term|[[dual loop]]}}
{{defn|A method of supervising contacts and wiring in a security system, so as to detect some faults or tampering.}}
{{term|[[DVD]]}}
{{defn|Digital Versatile Disc, a type of optical disc for distributing video recordings and data using an orange/red laser.}}
{{term|[[dynamic braking]]}}
{{defn|A braking system that extracts energy from a moving system to bring it to rest; a dynamic braking system generally is not used to hold a position of a stationary object.}}
{{term|[[dynamic demand (electric power)|dynamic demand]]}}
{{defn|A technique for load management on an electrical grid based on frequency measurement.}}
{{term|[[dynamic programming]]}}
{{defn|A technique for optimization of the solution of a problem by combining solutions to smaller sub-problems.}}
{{term|[[dynamic random-access memory]]}}
{{defn|A type of semiconductor memory where data is stored as electric charges on capacitors; the charges must be refreshed periodically or else they will leak away, losing the stored data.}}
{{term|[[dynamo]]}}
{{defn|A direct-current generator, whose exciting field is provided by an electromagnet.}}
{{glossary end}}
Line 296 ⟶ 551:
==E==
{{glossary}}
{{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|[[electret]]}}
{{
{{term {{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{
{{term|[[electric displacement field]]}}
{{defn|In Maxwell's equations, a vector field due to electric charges.}}
{{term|[[electric distribution systems]]}}
{{defn|That portion of an electrical grid that connects customers to substations or the bulk transmission system.}}
{{term|[[electric field gradient]]}}
{{defn|The rate of change of electric field with respect to distance.}}
{{term|[[electric field]]}}
{{defn|A vector field that exerts a force on electric charges.}}
{{term|[[electric generator]]}}
{{defn|A machine that converts mechanical energy to electrical energy by moving {{gli|conductor|conductors}} through magnetic fields.}}
{{term|[[electric motor]]}}
{{term|[[electric multiple unit]]}}
{{defn|Use of more than one electric locomotive on a train.}}
{{term|[[electric potential]]}}
{{term|[[electric power conversion]]}}
{{defn|Generally, changing the form of electric power.}}
{{term|[[electric power distribution]]}}
{{defn|In an electric grid, the network that brings power from a substation or bulk supply to individual customers.}}
{{term|[[Electric Power Research Institute]]}}
{{
{{term|[[electric power transmission]]}}
{{defn|The bulk movement of electric power for many customers from a generating plant to a local distribution network, usually at high voltage.}}
{{term|[[electric power]]}}
{{defn|The rate of transfer of electrical energy past a given point.}}
{{term|[[electric shock]]}}
{{defn|An injury caused to people or animals by electric current.}}
{{term|[[electrical cable]]}}
{{defn|A flexible conducting wire to carry electrical power or signals, usually covered with an insulating material.}}
{{term|[[electrical code]]}}
{{defn|A set of regulations for the use of electricity; they may vary from municipal to international in scope.}}
{{term|[[electrical conductivity]]}}
{{defn|A measure of a substance's ability to pass an electric current.}}
{{term|[[electrical conductor]]}}
{{defn|An object that carries an electric current, with little loss.}}
{{term|[[electrical contact]]}}
{{defn|A separable part of an electric device that carries current when touching another contact.}}
{{term|[[electrical discharge machining]] (EDM)}}
{{defn|Shaping of a work place by small sparks.}}
{{term|[[electrical element]]}}
{{defn|In circuit theory, a node at which some electrical property is concentrated (resistance, etc.).}}
{{term|[[electrical engineering]]}}
{{defn|The profession of applying electricity to practical problems.}}
{{term|[[electrical equipment]]}}
{{defn|Apparatus for generation, transmission or utilization of electric power.}}
{{term|[[electrical grid]]}}
{{defn|A geographically distributed system to connect source and users of electric power.}}
{{term|[[electrical impedance]]}}
{{defn|That property of a circuit that resists the passage of electric current, usually in the context of {{gli|alternating current}}.}}
{{term|[[electrical insulation paper]]}}
{{defn|A grade of paper used for insulation of transformers, electrical machines, capacitors, and some cables.}}
{{term|[[electrical insulation]]}}
{{defn|A material that resists electrical current flow.}}
{{term|[[electrical load]]}}
{{term|[[electrical machine]]}}
{{defn|Motors and generators, apparatus that converts between electrical power and mechanical power.}}
{{term|[[electrical measurements]]}}
{{defn|That branch of metrology concerned with electrical quantities.}}
{{term|[[electrical network]]}}
{{defn|A network of electrical components and conductors.}}
{{term|[[electrical polarity]]}}
{{defn|Identification of electrical terminals where current is flowing in the same direction relative to the device.}}
{{term|[[electrical steel]]}}
{{defn|Any of several types of steel used for manufacturing the magnetic field components of machines and transformers.}}
{{term|[[electrical substation]]}}
{{defn|A facility connecting a distribution network to a transmission network, usually with one or more transformers.}}
{{term|[[electrical technologist]]}}
{{defn|A specialist in applying electrical theory and technique to practical problems.}}
{{term|[[electrical wiring regulations]]}}
{{defn|The legal framework for electrical installations in buildings.}}
{{term|[[electrical wiring]]}}
{{defn|The installation of conductors, fixtures and protection devices for a structure or vehicle.}}
{{term|[[electricity meter]]}}
{{defn|An instrument to measure the electrical energy used by a customer for revenue purposes.}}
{{term|[[electricity pylon]]}}
{{defn|A structure, generally of wood or metal, to support wires.}}
{{term|[[electricity]]}}
{{defn|The set of physical phenomena associated with electric charges.}}
{{term|[[electrification]]}}
{{defn|Applying electric power to a process that was previously done by other means, or, development of an electric power system in a region that previously had none.}}
{{term|[[electroactive polymers]]}}
{{defn|A polymer that significantly changes size or shape when exposed to an electric field.}}
{{term|[[electrocardiograph]]}}
{{defn|A record of the electrical activity of the heart.}}
{{term|[[electrochemical engineering]]}}
{{defn|The profession of application of electrochemistry to practical problems.}}
{{term|[[electrodes]]}}
{{defn|An electrical contact that connects some medium to an electric circuit, such as in an electrochemical cell or a vacuum tube.}}
{{term|[[electro-diesel locomotive]]}}
{{defn|A railway locomotive with a diesel engine, generator, and electric driving motors that can be powered by the diesel engine or the track electrical supply.}}
{{term|[[electrodynamics]]}}
{{defn|The branch of physics that studies electrical charges and electrical currents.}}
{{term|[[electrolyte]]}}
{{defn|A liquid or solid medium that carries electric current in the form of ions.}}
{{term|[[electromagnet]]}}
{{defn|A magnet that generates a magnetic field from an {{gli|electric current}}.}}
{{term|[[electromagnetic compatibility]]}}
{{defn|The control of unwanted electromagnetic interference.}}
{{term|[[electromagnetic field]]}}
{{defn|The field produced by moving electric charges and magnetic fields.}}
{{term|[[electromagnetic induction]]}}
{{defn|The production of current in a circuit by the change of magnetic field intersecting the circuit.}}
{{term|[[electromagnetic radiation]]}}
{{defn|Radio waves, light and other radiation that travels through space at the speed of light.}}
{{term|[[electromagnetic spectrum]]}}
{{defn|The range of frequencies of electromagnetic radiation.}}
{{term|[[electromagnetic wave equation]]}}
{{defn|A second-order partial differential equation that describes the propagation of electromagnetic waves through a medium or in a vacuum.}}
{{term|[[electromagnetism]]}}
{{defn|The science of electric fields, magnetic fields, currents, charges, and forces.}}
{{term|[[electromechanical]]}}
{{defn|A system that has both an electrical component and a mechanical component, such as a motor or a relay.}}
{{term|[[electromote]]}}
{{defn|An 1882 demonstration of a prototype electric trolley bus.}}
{{term|[[electromotive force]]}}
{{defn|A difference in electrical potential between two points, such as produced by a battery or a generator.}}
{{term|[[electron microscope]]}}
{{defn|An instrument that provides highly magnified images by use of an electron beam.}}
{{term|[[electronic amplifier]]}}
{{defn|A device that increases the power of an electrical signal by electronic means.}}
{{term|[[electronic circuit]]}}
{{defn|A circuit using one or more electronic devices.}}
{{term|[[electronic component]]}}
{{defn|An active or passive element of an electronic circuit.}}
{{term|[[electronic control unit]]}}
{{defn|In an automobile, an embedded electronic system that controls some aspect of a vehicle (ignition, transmission, and so on).}}
{{term|[[electronic design automation]]}}
{{defn|A system in which a computer provides assistance to the designer of a device or system.}}
{{term|[[electronic engineering]]}}
{{defn|The profession of applying electronics to practical problems.}}
{{term|[[electronic filter]]}}
{{defn|A filter that alters some frequency-related characteristic of a signal.}}
{{term|[[electronics]]}}
{{defn|The study of the flow of electrons through a vacuum, gases or semiconductors.}}
{{term|[[electronic speed control]]}}
{{defn|A device for regulating the speed of a motor.}}
{{term|[[electrophorus]]}}
{{defn|An instrument used to produce electrostatic charge through electrostatic induction.}}
{{term|[[electrostatic motor]]}}
{{defn|A motor that relies on the forces generated by electric fields, instead of magnetic fields.}}
{{term|[[electrostatics]]}}
{{defn|The study of stationary electric charges and resulting forces.}}
{{term|[[embedded operating system]]}}
{{defn|The common operating environment that supports embedded software; it may be a highly tailored version of a general-purpose operating system, or written solely for the purpose of embedded system operations.}}
{{term|[[embedded software]]}}
{{defn|A firmware component of a microprocessor-controlled system.}}
{{term|[[embedded system]]}}
{{defn|A computer system that controls a device or system, with no or a minimal user interface; for example, the ignition system in a car may have a microprocessor to control it.}}
{{term|[[enameled wire]]}}
{{defn|Wire insulated with a thin flexible layer of enamel, used for electrical windings.}}
{{term|[[energy demand management]]}}
{{defn|A system to adjust energy demand to reduce costs.}}
{{term|[[energy economics]]}}
{{defn|A branch of economics concerned with energy supply and demand.}}
{{term|[[energy efficient transformer]]}}
{{defn|A power transformer designed to have lower than average energy loss.}}
{{term|[[energy returned on energy invested]]}}
{{defn|A measure of how long an energy producing system takes to replace the energy it took to make it.}}
{{term|[[energy subsidies]]}}
{{defn|Payments to a consumer or producer of electric energy that are used as incentives for production or consumption.}}
{{term|[[engine-generator]]}}
{{defn|A combination of an internal combustion engine and a generator, often used as a standby power plant.}}
{{term|[[ENIAC]]}}
{{defn|The first general purpose electronic digital computer.}}
{{term|[[Epstein frame]]}}
{{defn|An apparatus used for testing of magnetic materials.}}
{{term|[[equalization (audio)]]}}
{{defn|Adjustment of the frequency response of a system to improve its utility.}}
{{term|[[equalization (communications)]]}}
{{defn|Adjustment of the frequency spectrum of a signal to cancel out the effect of the frequency response of a communication path.}}
{{term|[[equivalent circuit]]}}
{{defn|In circuit theory, a simple combination of elements that behaves at its terminals like a more complex combination.}}
{{term|[[equivalent impedance transforms]]}}
{{defn|A mathematical method to determine values of an equivalent circuit.}}
{{term|[[error correction and detection]]}}
{{defn|Techniques used to improve reliability of computer memory or communications channels by including extra information along with the desired data.}}
{{term|[[exponential stability]]}}
{{defn|A system that settles to a steady state after a disturbance, at a rate proportional to exponential time.}}
{{term|[[extended Kalman filter]]}}
{{defn|A strategy for estimating an unknown value in a non-linear system by combining multiple measurements.}}
{{glossary end}}
Line 406 ⟶ 757:
==F==
{{glossary}}
{{term|[[farad]]}}
{{
{{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|[[feedback]]}}
{{defn|A system that samples part of its output and adds that to its input; feedback may be either positive or negative, aiding or opposing the initial input signal.}}
{{term|[[feed-in tariff]]}}
{{defn|A premium rate paid to distributed generators to encourage alternative energy sources.}}
{{term|[[ferrite core]]}}
{{defn|A magnetic core for an {{gli|inductor}} made from a metal oxide compound.}}
{{term|[[ferroelectricity]]}}
{{defn|The property of materials that spontaneously maintain an electrical polarization, as a ferromagnetic material maintains magnetic polarization.}}
{{term|[[fiber-optic cable]]}}
{{defn|A transmission medium that uses infrared energy or light to transmit information down a long thin transparent filament such as glass.}}
{{term|[[field effect transistor]]}}
{{defn|A transistor that relies on modulation of conductivity of a channel instead of injection of minority carriers as does a bipolar transistor.}}
{{term|[[field-oriented control]]}}
{{defn|A control strategy for variable frequency drives that models the magnetic field of the motor to control its torque.}}
{{term|[[filter (signal processing)|filter]]}}
{{defn|A circuit that selectively alters a signal based on its frequency components.}}
{{term|[[filter capacitor]]}}
{{defn|In a power supply, a {{gli|capacitor}} that smooths the {{gli|direct current|DC}} {{gli|voltage}} produced by a {{gli|rectifier}} stage.}}
{{term|[[finite impulse response]]}}
{{defn|A class of digital filters whose response to an impulse returns to zero in finite time.}}
{{term|[[firmware]]}}
{{defn|Software of a computer that is never or rarely altered during its working life, for example, the control computer program for an automotive ignition system.}}
{{term|[[Fleming valve]]}}
{{defn|The first important vacuum tube device, used as a radio detector.}}
{{term|[[Fleming's left-hand rule for motors]]}}
{{defn|A mnemonic to recall the relative orientation of current, magnetic field and resulting force for electric motors.}}
{{term|[[Fleming's right-hand rule]] for generators}}
{{defn|A mnemonic to recall the relative orientation of current, magnetic field and resulting force for electric generators.}}
{{term|[[fluorescent lamp]]}}
{{defn|A type of electric lamp that relies on a phosphor coating to produce visible light from the ultraviolet light generated by a mercury discharge.}}
{{term|[[flux linkage]]}}
{{defn|In a magnetic system, that part of the magnetic flux that passes through a given closed path, which may be a winding.}}
{{term|[[flyback converter]]}}
{{defn|A type of {{gli|voltage converter}} that stores energy in an inductor.}}
{{term|[[flyback transformer]]}}
{{defn|A type of transformer that recovers energy stored in its own core. Historically used in the deflection circuits of CRT display systems.}}
{{term|[[forward converter]]}}
{{defn|A type of {{gli|voltage converter}} that relies on {{gli|transformer}} action to couple energy to its output circuit.}}
{{term|[[fossil-fuel phase-out]]}}
{{defn|A plan to replace coal, oil, or natural gas fuel with other sources to produce electrical energy.}}
{{term|[[fossil-fuel power station]]}}
{{defn|A power plant using coal, oil, or natural gas fuel.}}
{{term|[[Fourier series]]}}
{{defn|A set of coefficients of sine and cosine waves; this can represent a time function as a function of frequency.}}
{{term|[[Fourier transform]]}}
{{defn|An algorithm for converting a continuous waveform in the time ___domain into an equivalent set of spectral components in the frequency ___domain.}}
{{term|[[free space optical communications]]}}
{{defn|Transfer of information from point to point by a beam of light or infrared energy, instead of a wired connection or radio waves.}}
{{term|[[frequency changer]]}}
{{defn|An electric machine used to transfer power between two networks with different frequencies, or, an electronic device (more usually called a frequency mixer) that changes the frequency of an input signal to some other frequency.}}
{{term|[[frequency modulation]]}}
{{defn|A method of impressing information on a carrier wave by changing its frequency.}}
{{term|[[frequency response]]}}
{{defn|The measure of the output of a system in response to an input of varying frequency.}}
{{term|[[full load current]]}}
{{defn|The current drawn by a motor or other electrical machine at its full rated power and standard voltage.}}
{{term|[[full-wave rectifier]]}}
{{defn|A rectifier circuit that converts both positive and negative parts of the input {{gli|alternating current}} waveform into a unidirectional, {{gli|direct current}}.}}
{{term|[[fuse (electrical)|fuse]]}}
{{defn|A circuit protective device that interrupts excessive {{gli|current}} by melting a metal strip.}}
{{term|[[fuzzy control]]}}
{{defn|A control system that relies on fuzzy logic instead of binary true/false conditions.}}
{{glossary end}}
Line 456 ⟶ 843:
==G==
{{glossary}}
{{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|[[gamma ray]]}}
{{defn|Electromagnetic radiation with wavelengths shorter than ten nanometres. Strictly: radiation that is produced in the nucleus of atoms.}}
{{term|[[gas-filled tube]]}}
{{defn|An electron tube device that relies on the presence of gas for operation, usually at less than atmospheric pressure.}}
{{term|[[gate turn-off thyristor]] (GTO)}}
{{defn|A four-layer power semiconductor device that can be turned on and off by signals at a control (gate) terminal.}}
{{term|[[Gauss's law]]}}
{{defn|A mathematical relation between the electric flux passing through a surface and the charge contained within that surface.}}
{{term|[[generator (circuit theory)|generator]]}}
{{defn|In {{gli|circuit theory}}, an ideal {{gli|voltage}} source or an ideal {{gli|current}} source, whose properties are independent of the connected {{gli|circuit}}.}}
{{term|[[governor (device)|governor]]}}
{{defn|A speed regulator for a machine such as a steam engine; an early important feedback control cybernetic system.}}
{{term|[[grid energy storage]]}}
{{defn|Any system tied to an electrical grid that stores electrical energy at low demand times and releases it to meet peak loads; it might be a centralized station like a pumped-storage hydroelectric plant, or might be distributed over many customer sites such as by the use of electric vehicle batteries.}}
{{term|[[grid-tie inverter]]}}
{{defn|A power inverter that allows synchronization with the electrical grid for export of energy surplus to the facility's needs.}}
{{term|[[ground (electricity)|ground]]}}
{{defn|A reference point for electrical potential; often connected to the Earth.}}
{{term|[[ground and neutral]]}}
{{defn|Protective and circuit return conductors in a wiring system.}}
{{term|[[ground-level power supply]]}}
{{defn|A system for providing powers for electric trams without overhead wires and without a permanently energized third rail.}}
{{term|[[growler (electrical device)|growler]]}}
{{defn|A test instrument that is used to diagnose some faults with AC motors.}}
{{term|[[GSM]]}}
{{defn|The second generation of cellular mobile phone technology, deployed since 1991 in Europe.}}
{{term|[[Gunn diode]]}}
{{defn|A two-terminal solid-state device that is used in microwave oscillators.}}
{{term|[[gyrotron]]}}
{{defn|A high-power vacuum tube oscillator that can produce microwave frequencies up to hundreds of gigahertz at power levels up to megawatts.}}
{{glossary end}}
Line 485 ⟶ 886:
==H==
{{glossary}}
{{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|[[headphone]]}}
{{defn|An audio transducer or pair of transducers arranged to be worn on (or in) the ear.}}
{{term|[[heat transfer]]}}
{{defn|The study of the flow of heat energy; heat transfer concerns dictate major design features of most electrical and electronic systems.}}
{{term|[[heatsink]]}}
{{defn|A structure intended to dissipate heat from an active device into the ambient environment.}}
{{term|[[Heaviside step function]]}}
{{defn|A mathematical unit step function useful in the solution of certain differential equations by the methods of operational calculus.}}
{{term|[[Helmholtz coil]]}}
{{defn|An arrangement of coils useful for producing a uniform magnetic field within a certain volume.}}
{{term|[[henry (unit)|henry]]}}
{{defn|The [[International System of Units|SI]] unit of inductance.}}
{{term|[[Hertz]]}}
{{defn|The [[International System of Units|SI]] unit of frequency, equivalent to one cycle per second.}}
{{term|[[heterodyne]]}}
{{defn|The process of mixing signals of a number of frequencies to produce new frequencies.}}
{{term|[[heterostructure]]}}
{{defn|A {{gli|semiconductor}} device built of two or more dissimilar materials.}}
{{term|[[Hi-Fi]]}}
{{defn|High Fidelity, the set of techniques for reproduction of sounds that appear natural in source.}}
{{term|[[high-voltage cable]]}}
{{defn|A flexible insulated electrical conductor designed to withstand a significant {{gli|voltage}}; "high" voltage may be hundreds or hundreds of thousands of volts, depending on the context.}}
{{term|[[high voltage]]}}
{{defn|Any voltage at which safety concerns apply; in some contexts, anything over 100 volts may be a high voltage; in electric power transmission, voltages over 66,000 volts are considered "high voltage".}}
{{term|[[high-pass filter]]}}
{{defn|An electrical network that tends to pass higher frequencies and block lower ones.}}
{{term|[[high-voltage direct current]]}}
{{defn|A system for power transmission that uses high {{gli|direct current|DC}} {{gli|voltage|voltages}} for reasons of economy or stability.}}
{{term|[[high-voltage switchgear]]}}
{{defn|Electrical apparatus designed for control of high-voltage circuits.}}
{{term|[[Hilbert transform]]}}
{{defn|A mathematical operation used in signal processing.}}
{{term|[[holography]]}}
{{defn|The technique of representing the image of a scene by a recording of interference patterns of the light field.}}
{{term|[[home appliance]]}}
{{defn|Any electrical appliance intended for use in a home.}}
{{term|[[homopolar generator]]}}
{{defn|A generator in which {{gli|current}} and {{gli|magnetic field}} direction are constant as the machine rotor revolves.}}
{{term|[[homopolar motor]]}}
{{defn|A motor that produces torque from a current and magnetic field that does not change direction.}}
{{term|[[horsepower]]}}
{{defn|A unit of {{gli|power}}, equivalent to around 746 watts.}}
{{term|[[hot wire barretter]]}}
{{defn|A current dependent resistor formed of a fine wire in an envelope, useful for regulating current.}}
{{term|[[humidistat]]}}
{{defn|A switch that operates automatically on detecting a change in moisture content of the air.}}
{{term|[[HVAC]]}}
{{defn|High Voltage Alternating Current; depending on context, this could be hundreds or hundreds of thousands of volts.}}
{{term|[[HVDC converter station]]}}
{{defn|An element of a high-voltage {{gli|direct current}} power transmission system; each end of the transmission line has a converter station connected to the local AC grid.}}
{{term|[[HVDC]]}}
{{defn|High Voltage Direct Current.}}
{{term|[[hybrid coil]]}}
{{defn|A kind of transformer used for bidirectional transmission of signals over one pair of wires, for example, as in an analog telephone set.}}
{{term|[[hydroelectricity]]}}
{{defn|The generation of electric power from the kinetic energy of falling water.}}
{{term|[[hydropower]]}}
{{defn|Power (now nearly always electric power) generated from falling water; hydroelectricity.}}
{{term|[[hysteresis]]}}
{{defn|A characteristic of a system where its state is history-dependent.}}
{{glossary end}}
Line 531 ⟶ 968:
==I==
{{glossary}}
{{term|[[IGBT]]}}
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|
{{term|[[industrial and multiphase power plugs and sockets]]}}{{defn|Electrical fittings used to connect cables to three-phase power circuits.}}
{{term|
{{term|[[infinite impulse response]]}}{{defn|A filter which, mathematically, never gets to a zero effect of an impulse at its input, though practically the response may become negligible after a definite time.}}
{{term|[[information appliance]]}}{{defn|Conceptually, an embedded computer system with a specialized user interface designed to simplify one task, such as e-mail or photos; a modern smart phone approaches this concept.}}
{{term|[[information theory]]}}{{defn|The mathematical study of information.}}
{{term|
{{term|[[input/output]] (I/O)}}{{defn|That part of a computer system devoted to exporting and importing data, for example, in human-readable form.}}
{{term|[[inrush current]]}}
{{term|
{{term|
{{defn| {{term|
{{defn| {{term|
{{term|
{{term|
{{defn| {{term|
{{defn| {{term|
{{term|
{{term|
{{term|
{{defn| {{term|
{{defn| {{term|
{{term|
{{defn| {{term|
{{defn| {{term|
{{term|
{{term|
{{glossary end}}
Line 579 ⟶ 1,024:
==J==
{{glossary}}
{{term|
{{term|
{{term|
{{term|
{{defn| {{term|
{{defn| {{term|[[joule]]}}
{{defn|Symbol: J, is a [[SI derived unit|derived unit]] of [[energy]] in the [[International System of Units]].<ref>{{SIbrochure8th|page=120}}</ref> It is equal to the energy transferred to (or [[work (physics)|work]] done on) an object when a [[force]] of one [[Newton (unit)|newton]] acts on that object in the direction of the force's motion through a distance of one [[metre]] (1 newton metre or N⋅m). It is also the energy dissipated as heat when an [[electric current]] of one [[ampere]] passes through a [[Electrical resistance and conductance|resistance]] of one [[ohm]] for one second. It is named after the English physicist [[James Prescott Joule]] (1818–1889).<ref>[https://web.archive.org/web/20060413141420/http://education.yahoo.com/reference/dictionary/entry/joule American Heritage Dictionary of the English Language], Online Edition (2009). Houghton Mifflin Co., hosted by [https://web.archive.org/web/20010502171832/http://education.yahoo.com/ Yahoo! Education].</ref><ref>''The American Heritage Dictionary'', Second College Edition (1985). Boston: Houghton Mifflin Co., p. 691.</ref><ref>''McGraw-Hill Dictionary of Physics'', Fifth Edition (1997). McGraw-Hill, Inc., p. 224.</ref>}}
{{glossary end}}
==K==
{{glossary}}
{{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{term|
{{defn| {{glossary end}}
Line 600 ⟶ 1,053:
==L==
{{glossary}}
{{term|[[Ladder network]]}}
{{defn|A string of many, often equally dimensioned, impedances connected between two reference voltages.}}
{{term|[[LAN]]}}
{{defn|Local Area Network, an interconnection of computers over a building or small campus.}}
{{term|[[Laplace transform]]}}
{{defn|A mathematical operation for solution of differential equations by transforming them to the s ___domain from the time ___domain.}}
{{term|[[laser diode]]}}
{{defn|A semiconductor device that produces coherent laser radiation when properly energized.}}
{{term|[[leakage inductance]]}}
{{defn|The inductance of a transformer that results from magnetic flux not linked by both primary and secondary windings.}}
{{term|[[light-emitting diode]]}}
{{defn|A semiconductor device that produces light or infrared or ultraviolet radiation when properly energized.}}
{{term|[[linear alternator]]}}
{{defn|An electrical machine that generates electric power from the relative straight-line motion of its parts.}}
{{term|[[linear motor]]}}
{{defn|An electrical machine that generates electric force in a straight line by the interaction of its moving parts and magnetic fields.}}
{{term|[[linear variable differential transformer]]}}
{{defn|A transducer that produces an electrical signal proportional to the movement between its parts.}}
{{term|[[Lineman (technician)|lineman]]}}
{{defn|A specialist technician who installs outside plant wiring (overhead circuits, power transmission lines).}}
{{term|[[Litz wire]]}}
{{defn|A kind of stranded wire used to minimize losses in coils.}}
{{term|[[load flow study]]}}
{{defn|A mathematical prediction of the flow of electric power in a network, based on a model of the actual or proposed system; necessary for planning of electrical grids.}}
{{term|[[load following power plant]]}}
{{defn|A power plant that can economically be operated over a significant range of output, so as to meet varying electric power demand.}}
{{term|[[load-loss factor]]}}
{{defn|A factor for estimating energy lost in a distribution network due to load current.}}
{{term|[[load management]]}}
{{defn|Any strategy for altering the operation of customer loads so as to reduce peak demand on an electrical grid.}}
{{term|[[load profile]]}}
{{defn|The daily, weekly, or annual plot of electrical load against time.}}
{{term|[[local positioning system]]}}
{{defn|A navigation system that doesn't cover the whole Earth; such as over a continent, or even within a building.}}
{{term|[[LORAN]]}}
{{defn|A radio navigation system developed from a World War II military system (GEE), used for civilian purposes till the 1980s.}}
{{term|[[Lorentz force law]]}}
{{defn|The mathematical relation between currents in conductors and the resulting magnetic forces between them.}}
{{term|[[lossless data compression]]}}
{{defn|Any data compression method where the source can be reconstructed exactly; where approximations are tolerable, lossy data compression can be used.}}
{{term|[[lossy data compression]]}}
{{defn|Any data compression method which allows only a close approximation of the source to be reconstructed; useful for images or music, where the human perceptual system compensates for the errors.}}
{{term|[[loudspeaker]]}}
{{defn|A transducer that converts electrical current into sound, perceptible to more than one listener.}}
{{term|[[low-noise amplifier]]}}
{{defn|In a satellite radio receiving system, an amplifier placed near the antenna.}}
{{term|[[low-noise block downconverter]]}}
{{defn|In a satellite radio receiving system, a device that amplifies and converts signals to a lower frequency band that will have lower losses in interconnecting cables.}}
{{term|[[low-pass filter]]}}
{{defn|An electric filter network that passes lower frequencies and blocks higher ones.}}
{{term|[[LTI system theory]]}}
{{defn|The theory of systems that, over a useful range, respond proportionally to inputs and don't change characteristics while responding.}}
{{term|[[lumen (unit)|lumen]]}}
{{defn|The [[International System of Units|SI]] unit of luminous flux, the energy of visible light.}}
{{term|[[lumped parameters]]}}
{{defn|Describes an electrical network where the circuit elements are small compared to the wavelengths of the signals passing through it.}}
{{term|[[Lyapunov stability]]}}
{{defn|A criterion for stability of a dynamical system; if disturbances from a stable point reduce and the system returns to that stable point, it can be said to be Lyapunov stable.}}
{{glossary end}}
Line 634 ⟶ 1,117:
==M==
{{glossary}}
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{{defn| {{term|[[magnetostriction]]}}
{{defn|A property of some materials that change shape when subject to a magnetic field.}}
{{term|[[magnifying transmitter]]}}
{{defn|A concept for a signal transmitter that used a resonant transformer to provide a high {{gli|voltage}}.}}
{{term|[[main distribution frame]]}}
{{defn|In a telephone central office, the equipment that connects to subscriber circuits.}}
{{term|[[mainframe computer]]}}
{{defn|A large centralized computer system, used for large volumes of data or supporting multiple interactive terminals, with large input/output capacity, generally expected to provide critical services to a business or institution with a predictable degree of reliability.}}
{{term|[[mains electricity]]}}
{{defn|Commercial electric power, purchased from an off-site source shared by many consumers. Regional supplies vary in {{gli|voltage}}, frequency, and technical standards.}}
{{term|[[mains hum]]}}
{{defn|Interference on an audio or visual signal related to the power line frequency.}}
{{term|[[marginal stability]]}}
{{defn|Said of a system that neither returns to its initial state when disturbed nor diverges to some unstable condition.}}
{{term|[[marine energy]]}}
{{defn|Any technique for extracting useful energy from tides, waves, or salinity or temperature gradients of the ocean.}}
{{term|[[Marx generator]]}}
{{defn|A kind of circuit for generating very high DC {{gli|voltage}} pulses.}}
{{term|[[Maser]]}}
{{defn|A device that produces microwave energy in a similar manner to a LASER.}}
{{term|[[maximum prospective short-circuit current]]}}
{{defn|The calculated value of current that could flow if a short circuit occurred; a parameter for selection of circuit protection devices.}}
{{term|[[Maxwell's equations]]}}
{{defn|The fundamental relations between electric and magnetic fields, expressed in concise mathematical form.}}
{{term|[[mechanical rectifier]]}}
{{defn|An electromechanical device for converting {{gli|alternating current}} to {{gli|direct current}}, using sets of contacts which operate in synchronism with the AC.}}
{{term|[[mechatronics]]}}
{{defn|Combinations of mechanical systems with electronics for sensing and control.}}
{{term|[[memristor]]}}
{{defn|A hypothetical non-linear passive two-terminal electrical component relating electric charge and magnetic flux linkage.}}
{{term|[[mercury-arc rectifier]]}}
{{defn|A mercury-arc valve; a vacuum tube device that converts {{gli|alternating current}} to {{gli|direct current}} by an arc in mercury vapor; displaced by solid-state devices, but formerly much used especially in high-voltage {{gli|direct current}} transmission.}}
{{term|[[mercury vapor lamp]]}}
{{defn|A lamp that generates light from a discharge struck in mercury vapor; formerly widely used in outdoor lighting, now replaced by lamps with better efficacy.}}
{{term|[[mesh analysis]]}}
{{defn|A strategy for solution of the {{gli|voltage}} distribution in some types of electrical networks.}}
{{term|[[mesh networking]]}}
{{defn|A topology where infrastructure nodes connect to other nodes such as to convey information.}}
{{term|[[Metadyne]]}}
{{defn|A DC electric machine with crossed fields and two sets of brushes, used as an amplifier or rotary DC transformer.}}
{{term|[[metal rectifier]]}}
{{defn|A {{gli|rectifier}} made from copper oxide or selenium; formerly widely used before development of silicon rectifiers.}}
{{term|[[micro combined heat and power]]}}
{{defn|Equipment that generates process or space heat and electric power, of a size useful for a single building.}}
{{term|[[microcontroller]]}}
{{defn|A microprocessor integrated with memory and input/output circuits, useful for embedded control.}}
{{term|[[microelectromechanical systems]]}}
{{defn|An electromechanical system of microscopic size; they may be sensors or actuators.}}
{{term|[[microelectronics]]}}
{{defn|That part of the field of electronics dealing with integrated circuits.}}
{{term|[[microgeneration]]}}
{{defn|Small-scale electric power production, to provide the needs of a small building or individual consumer.}}
{{term|[[microphone]]}}
{{defn|A {{gli|transducer}} that changes sound into electrical signals.}}
{{term|[[microprocessor]]}}
{{defn|A computer with its logical, arithmetic and control functions implemented on one or a few integrated circuits.}}
{{term|[[microstrip]]}}
{{defn|A planar transmission line that is fabricated by printed circuit board technology and is used for microwave-frequency signals}}
{{term|[[microstrip antenna]]}}
{{defn|A planar antenna that is fabricated by printed circuit board technology}}
{{term|[[microwave oven]]}}
{{defn|A heating appliance that uses microwave energy.}}
{{term|[[microwave radio]]}}
{{defn|The subset of radio technique using wavelengths that are in the range of 3 GHz or higher.}}
{{term|[[microwave]]}}
{{defn|Part of the radio spectrum with wavelengths shorter than 10 centimetres.}}
{{term|[[Millman's theorem]]}}
{{defn|A theorem stating the relation between branch currents and {{gli|voltage|voltages}} for multiple sources in parallel.}}
{{term|[[mineral-insulated copper-clad cable]]}}
{{defn|Cable with an outer metal cover and insulated by powdered inorganic material, suitable for high temperature; one kind of fire-resistant cable.}}
{{term|[[mobile phone]]}}
{{defn|A handset that connects to the public switched telephone network by radio.}}
{{term|[[Modbus]]}}
{{defn|A brand name for a serial protocol for industrial control equipment communication.}}
{{term|[[model predictive control]]}}
{{defn|A control strategy for process systems based on a mathematical model of the process and its disturbances.}}
{{term|[[modem]]}}
{{defn|Modulator-Demodulator, an interface between a computer system and a telephone network.}}
{{term|[[modulation transformer]]}}
{{defn|Part of a radio transmitter used to impress modulation on one amplifying stage.}}
{{term|[[modulation]]}}
{{defn|The impression of information on a carrier wave for transmission.}}
{{term|[[monolithic microwave integrated circuit]]}}
{{defn|An integrated circuit that operates in microwave frequencies and that can be fabricated by printed circuit board technology.}}
{{term|[[monoscope]]}}
{{defn|A raster scan video device that generates a single fixed image for test or identification purposes.}}
{{term|[[Moore's law]]}}
{{defn|The observation that the number of transistors possible in an integrated circuit doubles approximately every two years.}}
{{term|[[Morse code]]}}
{{defn|A method of transmitting text by long and short impulses and varying delays between them.}}
{{term|[[MOSFET]]}}
{{defn|Metal Oxide Semiconductor Field Effect Transistor, a class of transistor using a single type of charge carrier and with a very thin insulating layer between current channel and control gate. If you count those built into integrated circuits, nearly all transistors are MOSFETs.}}
{{term|[[motion control]]}}
{{defn|That part of automation that deals with accurately controlling the movements of machines.}}
{{term|[[motor controller]]}}
{{defn|Electrical apparatus that regulates and protects an electric motor, which may be as simple as an on-off switch or a servo system for precision machine tools.}}
{{term|[[motor soft starter]]}}
{{defn|A device that reduces the inrush current when an electric motor is first connected to the power supply.}}
{{term|[[MP3]]}}
{{defn|A standard for encoding audio in digital form.}}
{{term|[[MRI]]}}
{{defn|Magnetic Resonance Imaging, a technique for examining the interiors of, for example, medical patients, using sensitive measurements of the magnetic fields of atomic nuclei.}}
{{term|[[multics]]}}
{{defn|An influential early time-sharing computer operating system, first released in 1969.}}
{{term|[[multimeter]]}}
{{defn|A test instrument that can measure {{gli|current}}, {{gli|voltage}}, or {{gli|resistance}} (though not concurrently).}}
{{term|[[Multisim]]}}
{{defn|A brand of computer software for electronic circuit simulation.}}
{{glossary end}}
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==N==
{{glossary}}
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{{term|neural network}}{{defn|An {{gli|artificial neural network}}, or one of the [[biological neural network]]s that the artificial networks are inspired by.}}
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==O==
{{glossary}}
{{term|[[observability]]}}
{{term|
{{defn| {{term|[[ohm]]}}
{{
{{term|[[ohmmeter]]}}
{{defn|An instrument that measures electrical resistance.}}
{{term|[[Ohm's law]]}}
{{defn|The mathematical relationship between {{gli|voltage}}, {{gli|current}}, and {{gli|resistance}}.}}
{{term|[[one-line diagram]]}}
{{defn|A simplified schematic diagram of a power system.}}
{{term|[[on-premises wiring]]}}
{{defn|Telecommunications wiring owned by the customer.}}
{{term|[[open-circuit test]]}}
{{defn|A test, of a transformer or other device, with no load connected.}}
{{term|[[open-circuit voltage]]}}
{{defn|The {{gli|voltage}} developed at the terminals of a device with no load connected.}}
{{term|[[open-circuit time constant method]]}}
{{defn|A method for approximately evaluating the transfer function of an electrical network.}}
{{term|[[operational amplifier]]}}
{{defn|A type of amplifier with differential inputs, widely used in circuits where feedback determines the circuit properties.}}
{{term|[[optical fiber]]}}
{{defn|A glass or plastic fiber used to convey signals transmitted by visible light or infrared radiation.}}
{{term|[[optimal control]]}}
{{defn|The branch of control theory studying optimization of a control system to fit some optimization criterion.}}
{{term|[[oscillation]]}}
{{defn|A periodic cyclical motion or disturbance.}}
{{term|[[oscilloscope]]}}
{{defn|An instrument for graphically displaying a waveform as a function of time.}}
{{term|[[Oudin coil]]}}
{{defn|An early form of high-voltage induction coil identical in principle to a Tesla coil except for being constructed essentially as an auto-transformer.}}
{{term|[[out of phase]]}}
{{defn|The condition when AC generation sources are not synchronized.}}
{{term|[[overhead line]]}}
{{defn|Outside plant run on poles or other structures; power transmission or telecommunication wires.}}
{{term|[[oversampling]]}}
{{defn|Sampling a signal at a rate higher than required by the Nyquist criterion.}}
{{term|[[overshoot (signal)|overshoot]]}}
{{defn|A transient excursion of a signal beyond its stead state value.}}
{{term|[[overvoltage]]}}
{{defn|Application of more than rated {{gli|voltage}} to a device.}}
{{term|[[oxygen-free copper]]}}
{{defn|A grade of copper preferred for electrical applications for its low electrical resistance.}}
{{glossary end}}
Line 776 ⟶ 1,347:
==P==
{{glossary}}
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{{term|[[passivity (engineering)|passivity]]}}{{defn|Incapable of adding energy to a signal or process.}}
{{term|[[patch cables]]}}{{defn|Short cables with connectors, used to make connections between outlets of a patch panel or for temporary connections to a system under test.}}
{{term|[[peak demand]]}}{{defn|The maximum rate at which energy is consumed from an electrical grid; may be either an instantaneous measure or the maximum energy transferred in some interval such as 15 minutes.}}
{{term|[[Peltier–Seebeck effect]]}}{{defn|The thermoelectric effect, movement of heat due to electric current flow.}}
{{term|[[pentagrid converter]]}}{{defn|A type of self-oscillating vacuum tube used a frequency mixer in superheterodyne receivers.}}
{{term|[[pentode]]}}{{defn|Any five-electrode electron device, but usually a kind of vacuum tube.}}
{{term|
{{term|
{{term|[[permeability (electromagnetism)|permeability]]}}{{defn|The amount of magnetisation in a material resulting from an applied magnetic field.}}
{{term|[[phase converter]]}}{{defn|Electrical apparatus that converts power from a system of phases to another system, for example, converting single-phase power to three-phase.}}
{{term|[[phase-fired controllers]]}}{{defn|An AC power controller that adjusts the effective value of output by switching on at a variable time phase in the AC cycle.}}
{{term|
{{term|[[phase modulation]]}}{{defn|Impressing information on a carrier wave by advancing or delaying the waveform slightly; related to frequency modulation.}}
{{term|[[phasor (electronics)|phasor]]}}{{defn|A vector representing a signal of a given frequency in phase space.}}
{{term|[[phasor measurement unit]]}}{{defn|A system that measures the timing and amplitude of {{gli|voltage|voltages}} and {{gli|current|currents}} on an electrical grid, synchronized over a wide geographic area; the resulting measurements can be used to manage power flow on the grid.}}
{{term|[[phonograph]]}}{{defn|A record player, a device that converts the mechanical movements of a stylus in a disk or cylinder recording groove into sound.}}
{{term|
{{term|[[photodetector]]}}{{defn|Any device that detects visible light.}}
{{term|
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{{term|
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{{term|[[PID controller]]}}{{defn|A process control system that has proportional, integral and derivative terms in its response to errors between measured value and setpoint.}}
{{term|[[piezoelectric effect]]}}{{defn|Production of a {{gli|voltage}} in response to mechanical pressure or mechanical deformation.}}
{{term|[[piezoelectric motor]]}}{{defn|A type of motor that uses {{gli|piezoelectric effect|piezoelectric}} elements to generate force.}}
{{term|
{{term|[[planar graph]]}}{{defn|In network theory, a set of nodes and interconnecting lines that can be given in one plane without crossing lines.}}
{{term|
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{{term|
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{{term|
{{term|[[polyphase system]]}}{{defn|An {{gli|alternating current}} power transmission system using three or more wires, each of which carries a current that is displaced in time with respect to the others.}}
{{term|[[Pontryagin's minimum principle]]}}{{defn|A mathematical principle used in the theory of optimal control.}}
{{term|
{{term|
{{term|[[potential difference]]}}{{defn|A {{gli|voltage}} difference, the amount of work required to bring a test charge from one point to another divided by charge magnitude.}}
{{term|
{{term|
{{term|[[power cable]]}}{{defn|Flexible insulated electrical conductors used to transmit electric power.}}
{{term|[[power conditioner]]}}{{defn|Any system intended to alter some property of the bulk power supply to improve it for some application; such as filters, surge suppressors, voltage regulators, uninterruptible power supplies, and many others.}}
{{term|
{{term|
{{term|[[power distribution]]}}{{defn|That portion of an electrical grid between the substation or bulk supply and the end consumer.}}
{{term|
{{term|[[power engineering]]}}{{defn|That part of electrical engineering that deals with the generation, distribution and consumption of electrical power.}}
{{term|
{{term|
{{term|[[power-flow study]]}}{{defn|A load flow study; mathematical prediction of the magnitudes and direction of power flow in an existing or planned power grid; an essential part of grid management.}}
{{term|
{{term|
{{term|[[power inverter]]}}{{defn|A DC to AC power converter.}}
{{term|
{{term|
{{term|
{{term|[[power rating]]}}{{defn|The nominal power that an apparatus or machine can handle, with specified or customary temperature rise and life expectancy.}}
{{term|[[power quality]]}}{{defn|Conformance of an electrical power supply with its specifications.}}
{{term|
{{term|[[power supply]]}}{{defn|A subsystem of a computer or other electronic device that turns electric power from a wall plug or batteries into a form suitable for use by the system.}}
{{term|[[power-system automation]]}}{{defn|The implementation of power-operated switching and control that allows automatic operation of power system elements, instead of manual operation.}}
{{term|[[power-system protection]]}}{{defn|The technology of limiting the spread of failures of a power system to a minimum, and of preventing permanent damage to apparatus or conductors by such faults.}}
{{term|[[printed circuit board]]}}{{defn|An etched wiring assembly for interconnection of electronic components.}}
{{term|[[printer (computing)|printer]]}}{{defn|A device that makes permanent human readable images and text from computer data.}}
{{term|[[process control]]}}{{defn|The field of study of automatic control of processes.}}
{{term|[[programmable logic controller]]}}{{defn|A computer system designed to be rugged enough for industrial use and with a programming environment highly tuned to the ___domain of industrial control problems.}}
{{term|
{{term|[[protective relay]]}}{{defn|An electromechanical or electronic device that detects faults on a power system and can signal circuit breakers to operate.}}
{{term|[[proximity effect (electromagnetism)|proximity effect]]}}{{defn|The increase in circuit resistance when the magnetic fields of multiple AC currents interact.}}
{{term|
{{term|
{{term|[[pulse-amplitude modulation]] (PAM)}}{{defn|Transmission of information by varying the magnitude of a stream of pulses of fixed frequency.}}
{{term|
{{term|[[pumped-storage hydroelectricity]]}}{{defn|A grid energy storage system that pumps water uphill for later use by a hydroelectric generator plant.}}
{{term|[[push switch]]}}{{defn|A device that closes or opens an electrical circuit when pushed.}}
{{term|[[push–pull converter]]}}{{defn|A converter with two sets of primary switching elements so that the transformer primary {{gli|voltage}} can be reversed on each cycle.}}
{{glossary end}}
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==Q==
{{glossary}}
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==R==
{{glossary}}
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{{term|[[reciprocity (electrical networks)]]}}{{defn|A theorem that states that the current injected into one point in a network will produce a {{gli|voltage}} at a second point that is identical to the voltage produced at the first point by injection of the same current at the first point}}
{{term|[[reciprocity (electromagnetism)]]}}{{defn|An observation that electric currents and electric fields can be analyzed from either point of view as regards the source of the energy in the system; for example, in radio, a good transmitting antenna is generally also a good receiving antenna.}}
{{term|[[record player]]}}{{defn|A phonograph; a device that turns the variations in a disk or cylinder recording groove into sound.}}
{{term|[[rectifier]]}}{{defn|A device that converts {{gli|alternating current}} (which periodically reverses) to {{gli|direct current}} that flows in only one direction; may be a solid-state, vacuum tube or electromechanical device.}}
{{term|[[rectiformer]]}}{{defn|A combination of a transformer and a rectifier, used in electrochemical processes or supply of electrostatic precipitators.}}
{{term|[[recursive least squares filter]]}}{{defn|An algorithm for a digital filter system.}}
{{term|[[Reed switch]]}}{{defn|An electrical switch made of two thin strips of ferromagnetic metal, which touch when subject to a magnetic field.}}
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==S==
{{glossary}}
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{{term|[[semiconductor device]]}}{{defn|A device that relies on substances with electrical conductivity between that of insulators and conductors; the controllable conductivity of these materials makes most of modern electronics possible.}}
{{term|[[semiconductor fabrication]]}}{{defn|The process of turning the raw source of silicon into transistors and integrated circuits.}}
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{{glossary end}}
Line 1,055 ⟶ 1,627:
==T==
{{glossary}}
{{term|
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{{term|[[telecommunication]]}}{{defn|The field that deals with transmission of information over distances longer than can be covered by an unaided human.}}
{{term|[[Telecommunications Industry Association]]}}{{defn|A US based trade association that develops technical standards.}}
{{term|[[telegraph]]}}{{defn|A system for transmitting text messages, by wire or other means.}}
{{term|[[telegrapher's equations]]}}{{defn|Coupled linear partial differential equations that relate the voltage and current on a transmission line.}}
{{term|
{{term|[[telephone line]]}}{{defn|Outside plant that connects a central office to subscriber equipment.}}
{{term|
{{term|
{{term|
{{term|
{{term|[[Tesla coil]]}}{{defn|A kind of resonant transformer capable of very high voltages; almost identical to an Oudin coil except that it has separately wound primary and secondary.}}
{{term|[[tetrode]]}}{{defn|An electron device, nearly always a vacuum tube, with four internal active electrodes.}}
{{term|[[thermionic emission]]}}{{defn|Emission of electrons from a hot surface; the Edison Effect was an early instance of description of this phenomenon.}}
{{term|[[thermistor]]}}{{defn|A temperature sensitive resistor with a large, somewhat variable, temperature coefficient of resistance.}}
{{term|
{{term|[[thermoelectric effect]]}}{{defn|The conversion between heat flow and current flow, and the reverse.}}
{{term|[[thermostat]]}}{{defn|A temperature sensing switch.}}
{{term|[[Thévenin theorem]]}}{{defn|A theorem which states that any network of current sources, voltage sources and resistors can be simplified to an equivalent network with only a {{gli|voltage}} source and series impedance; the dual of Norton's Theorem.}}
{{term|[[third rail]]}}{{defn|An energized conductor in the track bed, using a sliding contact to transfer power to an electric train.}}
{{term|[[three-phase AC railway electrification]]}}{{defn|Application of three-phase power to railways.}}
{{term|[[three-phase electric power]]}}{{defn|Electric power transmission using three conductors carrying currents which peak at separate evenly spaced times in each cycle; widely used for motors.}}
{{term|[[thyristor]]}}{{defn|A four layer semiconductor device that stands off applied {{gli|voltage}} until triggered.}}
{{term|
{{term|
{{term|
{{term|[[time-invariant system]]}}{{defn|A systems whose characteristics don't vary significantly with time.}}
{{term|[[topology (electrical circuits)|topology]]}}{{defn|The shape of an electrical network, independent of its size or values.}}
{{term|
{{term|[[total harmonic distortion]] (THD)}}{{defn|A measure of the magnitude of harmonically-related frequency components a signal processing stage adds.}}
{{term|[[traction battery]]}}{{defn|A battery used to store energy for propelling a wheeled electric vehicle.}}
{{term|
{{term|
{{term|
{{term|
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{{term|[[transducer]]}}{{defn|An instrument that converts a physical quantity into another electrical or physical quantity.}}
{{term|[[transfer function]]}}{{defn|The mathematical relation between input and output, usually expressed in terms of frequency or complex frequency (s-___domain).}}
{{term|[[transformer oil testing]]}}{{defn|Examination of transformer oil for its insulating strength, dissolved moisture and other properties, to ensure it is still suitable for use.}}
{{term|
{{term|
{{term|[[transformerboard]]}}{{defn|A kind of insulating paperboard used for internal structures of large oil filled power transformers.}}
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{{term|[[transmission system operator]]}}{{defn|A corporation that runs the transmission system between sources of power and distribution substations.}}
{{term|[[transmission tower]]}}{{defn|A structure for support of overhead transmission wires.}}
{{term|[[transmitter]]}}{{defn|Apparatus that prepares a signal for emission into some medium, such as a radio transmitter or a sonar transmitter.}}
{{term|[[traveling-wave tube]]}}{{defn|A type of microwave amplifier vacuum tube.}}
{{term|[[trembler coil]]}}{{defn|A kind of high-voltage coil that includes an interrupting mechanism, formerly used in automobile ignition systems.}}
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{{term|[[twisted pair]]}}{{defn|Two wires twisted around each other, possibly covered with an overall sheath; this configuration rejects some kinds of interference.}}
{{term|[[two-phase electric power]]}}{{defn|An electric power system using two sets of {{gli|alternating current|alternating currents}}, displaced in time by a quarter period.}}
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{{glossary end}}
Line 1,129 ⟶ 1,700:
==U==
{{glossary}}
{{term|
{{defn| {{term|
{{defn| {{term|[[ultrasonics]]}}
{{defn|Term for the field of study pertaining to pressure oscillations in air or other media that are above the range of human hearing.}}
{{term|[[ultrasound]]}}
{{defn|Sound having a frequency above the range of normal human hearing. A portmanteau of the former description of 'ultrasonic sound'}}
{{term|[[undersampling]]}}
{{defn|Sampling a signal at less than the Nyquist rate; can produce alias frequencies or other artifacts.}}
{{term|[[unijunction transistor]]}}
{{defn|A three terminal semiconductor device with a definite switching characteristic and only one PN junction.}}
{{term|[[unipolar motor]]}}
{{defn|A heteropolar motor; all currents in this design flow in only one direction.}}
{{term|[[unshielded twisted pair]]}}
{{defn|Two wires wrapped around each other, but without a conductive cover.}}
{{term|[[upsampling]]}}
{{defn|Sampling at greater than the Nyquist rate, which makes filter design easier.}}
{{term|[[utility frequency]]}}
{{defn|60 or 50 cycles per second, used for electric power.}}
{{term|[[utility pole]]}}
{{defn|A columnar structure that carries wires for electrical power distribution, cable television, telephone or similar services.}}
{{glossary end}}
Line 1,147 ⟶ 1,728:
==V==
{{glossary}}
{{term|
{{defn| {{term|[[vacuum tube]]}}
{{defn|An electron device that relies on flow of electrons through a vacuum or low-pressure gas; a valve. The first electronic devices that could amplify.}}
{{term|[[HVDC converter|valve]]}}
{{defn|A switching element (mercury arc, {{gli|thyristor}}, or other device) in a high-voltage {{gli|direct current}} converter; each phase contains two or more valves, which may be series-connected for higher voltages. Or, a vacuum tube.}}
{{term|[[variable capacitor]]}}
{{defn|A capacitor whose value can be changed, by rotating a shaft, squeezing a plate or by an electrical signal; for example, as used to tune a radio.}}
{{term|[[variable-frequency drive]]}}
{{defn|A power converter that varies the speed of an AC motor by changing its frequency; usually, today, a solid-state device.}}
{{term|[[Variac]]}}
{{defn|One brand of adjustable transformer, that can essentially continuously vary the ratio between primary and secondary.}}
{{term|[[varicap]]}}
{{defn|Variable capacitor{{Snd}} usually a diode whose reverse-biased junction capacitance can be varied by applied {{gli|voltage}}.}}
{{term|[[varistor]]}}
{{defn|Variable resistor{{Snd}} a protective device that has a high resistance at low voltage but momentarily switches to lower resistance on exposure to a high voltage.}}
{{term|[[vector control (motor)|vector control]]}}
{{defn|A strategy for control of variable-speed motor drives.}}
{{term|[[vector group]]}}
{{defn|The classification of the connections of a polyphase transformer.}}
{{term|[[vehicle-to-grid]]}}
{{defn|A concept to use electric vehicle batteries as a form of grid energy storage.}}
{{term|[[vehicular automation]]}}
{{defn|Automatic systems to assist, or replace, the driver of a vehicle.}}
{{term|[[Versorium]]}}
{{defn|An antique version of an electroscope.}}
{{term|[[vibrator (electronic)|vibrator]]}}
{{defn|An electromechanical interrupter, part of a DC-to-AC converter in a battery-operated vacuum tube radio, or similar application. Some had additional contacts to act as a synchronous rectifier.}}
{{term|[[video camera tube]]}}
{{defn|A family of vacuum tube devices used to pick up images and transmit them electronically.}}
{{term|[[video processing]]}}
{{defn|The techniques used to enhance video images.}}
{{term|[[virtual instrumentation]]}}
{{defn|A software-intensive measuring system that can be programmed to emulate any of a number of conventional measuring instruments, or some combination of measuring functions.}}
{{term|[[virtual power plant]]}}
{{defn|A strategy for managing a collection of disparate power sources, interconnected with a communications network, as if they were a single centralized power plant.}}
{{term|[[VLSI]]}}
{{defn|Very Large Scale Integration, the ability to put hundreds of thousands of interconnected transistors onto one chip.}}
{{term|[[volt]]}}
{{defn|The [[International System of Units|SI]] unit of electrical potential difference; moving a charge of one coulomb through a potential of one volt transfers one joule of energy.}}
{{term|[[voltage]]}}
{{defn|The electric potential difference between two points.}}
{{term|[[voltage compensation]]}}
{{defn|Generally, adjustment of a voltage source to compensate for voltage drop; techniques differ widely between a computer power supply and a long-distance power line.}}
{{term|[[voltage-controlled amplifier]]}}
{{defn|An amplifier that has its gain controlled by a {{gli|voltage}} signal.}}
{{term|[[voltage controller]]}}
{{defn|A device that adjusts the (effective) {{gli|voltage}} to a load.}}
{{term|[[voltage converter]]}}
{{defn|Any device that changes electric power at one {{gli|voltage}} to power at a second; a transformer is a common example of an AC voltage converter.}}
{{term|[[voltage division]]}}
{{defn|A circuit that produces an output {{gli|voltage}} that is some, perhaps adjustable, fraction of the input voltage.}}
{{term|[[voltage doubler]]}}
{{defn|A rectifier circuit that can product an output DC {{gli|voltage}} of nearly twice the input AC voltage.}}
{{term|[[voltage regulation]]}}
{{defn|A measure of how a source maintains its output {{gli|voltage}} for varying load.}}
{{term|[[voltage regulator]]}}
{{defn|A system that automatically stabilizes the {{gli|voltage}} at which power is supplied to a downstream system.}}
{{term|[[voltage source]]}}
{{defn|In circuit theory, a hypothetical element that maintains a specified {{gli|voltage}} between its terminals independent of the current through it.}}
{{term|[[voltage spike]]}}
{{defn|A transient electrical {{gli|voltage}} higher than normal appearing on an electrical supply.}}
{{term|[[voltage-to-current converter]]}}
{{defn|A circuit that produces an output current proportional to an input {{gli|voltage}}.}}
{{term|[[volt-ampere]]}}
{{defn|The unit of apparent power in an AC circuit.}}
{{term|[[voltmeter]]}}
{{defn|An instrument for measuring potential difference.}}
{{glossary end}}
Line 1,188 ⟶ 1,802:
==W==
{{glossary}}
{{term|
{{defn| {{term|
{{defn| {{term|[[watt]]}}
{{defn|The [[International System of Units|SI]] unit of power, work done per unit time.}}
{{term|[[wattmeter]]}}
{{defn|An instrument that measures electrical power.}}
{{term|[[Waveguide (electromagnetism)|waveguide]]}}
{{defn|A tubular structure that guides electromagnetic waves, much used at microwave frequencies; an optical fiber is a kind of optical waveguide.}}
{{term|[[weber (unit)|weber]]}}
{{defn|The [[International System of Units|SI]] unit of magnetic flux.}}
{{term|[[Line isolation transformer|wet transformer]]}}
{{defn|In telephone systems, a matching transformer that can operate while carrying a substantial DC "wetting" current.}}
{{term|[[Wien bridge oscillator]]}}
{{defn|A type of electronic oscillator that generates sine waves and is based on a bridge circuit.}}
{{term|[[Wiener filter]]}}
{{defn|A class of filters used in signal processing, used to fit an estimate to noisy signal data.}}
{{term|[[Williams tube]]}}
{{defn|A cathode ray vacuum tube used as an early form of computer memory.}}
{{term|[[wind farm]]}}
{{defn|An array of two or more wind turbines, usually sharing a substation.}}
{{term|[[wind power]]}}
{{defn|Generation of electricity (sometimes mechanical power) from wind.}}
{{term|[[wind turbine]]}}
{{defn|A rotating machine that extracts energy from wind.}}
{{term|[[wire]]}}
{{defn|A strand of metal much, much, longer than it is wide; a conductor, often coated with insulation.}}
{{term|[[wireless network]]}}
{{defn|Data network relying on radio for the connection to end device; may span a building or a larger area.}}
{{term|[[wireless telegraphy]]}}
{{defn|Transmission of text by radio; usually implies Morse or radio-teletype.}}
{{glossary end}}
==X==
{{glossary}}
{{term|[[X-ray]]}}
{{defn|Electromagnetic radiation with wavelengths shorter than ten nanometres. Strictly: radiation that is produced in the electron shell of atoms.}}
{{term|[[X-ray lithography]]}}
{{defn|A developing technique for production of very high density structures in integrated circuits.}}
{{glossary end}}
==Y==
{{glossary}}
{{term|[[Yagi antenna]]}}
{{defn|A type of radio antenna using a feeder element, one or more parasitic reflector elements, and one or more director parasitic elements to provide a directional characteristic; the classic home TV rooftop antenna was usually a Yagi antenna.}}
{{term|[[Y-Δ transform|Y-delta transform]]}}
{{defn|A mathematical technique in circuit analysis to simplify a circuit.}}
{{glossary end}}
==Z==
{{glossary}}
{{term|[[Zener diode]]}}
{{term|[[Ziegler-Nichols tuning method]]}}
{{defn|It is a heuristic method of tuning a PID controller.}}
{{term|[[zigzag transformer]]}}
{{defn|A multiwinding three phase transformer, sometimes used for grounding.}}
{{term|[[Z-transform]]}}
{{defn|A mathematical operation that converts a set of evenly spaced measurements of an analog signal into a series of frequency components.}}
{{glossary end}}
Line 1,233 ⟶ 1,871:
*[[Glossary of mechanical engineering]]
*[[Glossary of structural engineering]]
==References==
{{Reflist}}
{{Engineering fields}}
{{Glossaries of science and engineering}}
[[Category:Electrical
[[Category:Electronic engineering]]
[[Category:Glossaries of science|electrical and electronics engineering]]
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[[Category:Wikipedia glossaries using description lists]]
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