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impedanceenUK
im·ped·ance I0055200 (ĭm-pēd′ns)n.1. Symbol Z A measure of the total opposition to current flow in an alternating current circuit, made up of two components, ohmic resistance and reactance, and usually represented in complex notation as Z = R + iX, where R is the ohmic resistance and X is the reactance.2. An analogous measure of resistance to an alternating effect, as the resistance to vibration of the medium in sound transmission.impedance (ɪmˈpiːdəns) n1. (Electronics) a measure of the opposition to the flow of an alternating current equal to the square root of the sum of the squares of the resistance and the reactance, expressed in ohms. Symbol: Z 2. (Electronics) a component that offers impedance3. (General Physics) Also called: acoustic impedance the ratio of the sound pressure in a medium to the rate of alternating flow of the medium through a specified surface due to the sound wave. Symbol: Za 4. (General Physics) Also called: mechanical impedance the ratio of the mechanical force, acting in the direction of motion, to the velocity of the resulting vibration. Symbol: Zm im•ped•ance (ɪmˈpid ns)
n. 1. the total opposition to alternating current by an electric circuit, equal to the square root of the sum of the squares of the resistance and reactance of the circuit and usu. expressed in ohms. 2. the ratio of the force on a system undergoing harmonic motion to the velocity of the particles in the system. [1886] im·ped·ance (ĭm-pēd′ns) A measure of the opposition to the flow of an electric current through a circuit of alternating current. Impedance is measured in ohms.Thesaurus| Noun | 1. |  impedance - a material's opposition to the flow of electric current; measured in ohmselectric resistance, electrical resistance, ohmic resistance, resistivity, resistanceelectrical phenomenon - a physical phenomenon involving electricityohmage - the ohmic resistance of a conductor |
TranslationsimpedanceenUK
impedance, in electricity, measure in ohms of the degree to which an electric circuit resists the flow of electric current when a voltage is impressed across its terminals. Impedance is expressed as the ratio of the voltage impressed across a pair of terminals to the current flow between those terminals. When a circuit is supplied with steady direct current, the impedance equals the total resistanceresistance,
property of an electric conductor by which it opposes a flow of electricity and dissipates electrical energy away from the circuit, usually as heat. Optimum resistance is provided by a conductor that is long, small in cross section, and of a material that conducts
..... Click the link for more information. of the circuit. The resistance depends upon the number of electrons that are free to become part of the current and upon the difficulty that the electrons have in moving through the circuit. When a circuit is supplied with alternating current, the impedance is affected by the inductanceinductance,
quantity that measures the electromagnetic induction of an electric circuit component; it is a property of the component itself rather than of the circuit as a whole.
..... Click the link for more information. and capacitancecapacitance,
in electricity, capability of a body, system, circuit, or device for storing electric charge. Capacitance is expressed as the ratio of stored charge in coulombs to the impressed potential difference in volts.
..... Click the link for more information. in the circuit. When supplied with alternating current, elements of the circuit that contain inductance or capacitance build up voltages that act in opposition to the flow of current. This opposition is called reactance, and it must be combined with the resistance to find the impedance. The reactance produced by inductance is proportional to the frequency of the alternating current. The reactance produced by capacitance is inversely proportional to the frequency of the alternating current. In order for a source of electricity that has an internal impedance to transfer maximum power to a device that also has an impedance, the two impedances must be matched. For example, in the simple case of pure resistances, the resistance of the source must also equal the resistance of the device. Impedance matching is important in any electrical or electronic system in which power transfer must be maximized.impedance[im′pēd·əns] (electricity) electrical impedance (physics) The ratio of a sinusoidally varying quantity to a second quantity which measures the response of a physical system to the first, both being considered in complex notation; examples are electrical impedance, acoustic impedance, and mechanical impedance. Also known as complex impedance. The ratio of the greatest magnitude of a sinusoidally varying quantity to the greatest magnitude of a second quantity which measures the response of a physical system to the first; equal to the magnitude of the quantity in the first definition. impedanceIn alternating-current electric circuits, a quantitative measure of the opposition to the flow of current upon the application of voltage; measured in ohms.impedance1. a measure of the opposition to the flow of an alternating current equal to the square root of the sum of the squares of the resistance and the reactance, expressed in ohms. 2. a component that offers impedance 3. the ratio of the sound pressure in a medium to the rate of alternating flow of the medium through a specified surface due to the sound wave. 4. the ratio of the mechanical force, acting in the direction of motion, to the velocity of the resulting vibration. impedance (electronics, physics)Opposition to flow of alternatingcurrent. Impedance consists of resistance plus reactance(capacitive or inductive). Measured in Ohms.impedance(1) The opposition to the flow of alternating current in a circuit. Represented by the letter "Z" and measured in ohms, impedance is the combination of resistance, inductance and capacitance of the circuit. See ohm.
(2) The opposition that a speaker produces to the alternating current coming from an amplifier. The lower the impedance, the more power required. Most speakers have an impedance of four to eight ohms. See ohm.
See impedanceimpedanceenUK
impedance [im-pe´dans] 1. obstruction or opposition to passage or flow, as of an electric current or other form of energy.2. the resistance in alternating current circuits, represented by the letter Z in mathematical formulas. Medical equipment is often rated according to impedance to allow for optimum performance by matching impedance ratings. A transformer can be used between components to cause the impedances of unequal systems to match.acoustic impedance an expression of the opposition to passage of sound waves, being the product of the density of a substance and the velocity of sound in it.im·ped·ance (im-pē'dăns), 1. Total opposition to flow. In electricity, when flow is steady, impedance is simply the resistance, for example, the driving pressure per unit flow; when flow is changing, impedance also includes the factors that oppose changes in flow. Thus, deviations of impedance, from simple ohmic resistance because of the effects of capacitance and inductance, become more important in alternating current as the frequency of oscillations increases. In fluid analogies (for example, pulsatile flow of blood, to-and-fro flow of respiratory gas), impedance depends not only on viscous resistance but also on compressibility, compliance, inertance, and the frequency of imposed oscillations. 2. Resistance of an acoustic system to being set in motion. Impedance Cardiac pacing The total opposition that a circuit presents to alternating electrical current. Cf Resistance. im·ped·ance (im-pē'dăns) 1. Opposition to flow of gases, liquids, or electrical current. 2. Resistance of an acoustic system to being set in motion. impedance any resistance to the flow of fluids moved by a series of pulses, such as blood flow.LegalSeeAdmittanceFinancialSeeOhmSee IMPED
See GMT / UTCimpedanceenUK
Related to impedance: impedance matching, inductance, acoustic impedanceSynonyms for impedancenoun a material's opposition to the flow of electric currentSynonyms- electric resistance
- electrical resistance
- ohmic resistance
- resistivity
- resistance
Related Words- electrical phenomenon
- ohmage
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