impedance
Americannoun
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Electricity. 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 usually expressed in ohms. Z
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Also called mechanical impedance. Physics. the ratio of the force on a system undergoing simple harmonic motion to the velocity of the particles in the system.
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something that impedes; an obstacle or hindrance.
noun
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Z. 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
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a component that offers impedance
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Also called: acoustic impedance. Za. 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
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Also called: mechanical impedance. Zm. the ratio of the mechanical force, acting in the direction of motion, to the velocity of the resulting vibration
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A measure of the opposition to the flow of alternating current through a circuit. Impedance is measured in ohms. The resistance of a circuit to direct current (also measured in ohms) is generally not the same as its impedance, due to the effects of capacitance and induction in and among the components of the circuit.
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See also impedance matching
Discover More
The term impedance is most often encountered in dealing with antennas and speakers in television, stereo, and radio systems.
Other Word Forms
Etymology
Origin of impedance
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
To evaluate the Hina battery, Schütte and colleagues examined 120 sodium-ion cells using impedance spectroscopy, a non-destructive method that measures battery uniformity.
From Science Daily ● Jun. 21, 2026
Rather than relying on external electronics, converters, or batteries, the electrolyzer adjusts its electrical characteristics through its own thermal and impedance properties.
From Science Daily ● Jun. 11, 2026
To make that diagnosis, gastroenterologists can do a test called a pH impedance study.
From Washington Post ● Feb. 27, 2023
That’s because Samsung required you to touch two fingers on the watch’s buttons to create a circuit for bioelectrical impedance analysis.
From The Verge ● Jul. 27, 2022
While many were probably prepared to encounter curious phenomena of impedance in the use of a condenser discharged disruptively, the experiments shown were extremely interesting on account of their paradoxical character.
From The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting by Thomas Commerford Martin
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
