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impedance

 - 5 dictionary results

im⋅ped⋅ance

[im-peed-ns]
–noun
1. 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. Symbol: Z
2. 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.
3. something that impedes; an obstacle or hindrance.

Origin:
1886; impede + -ance; term introduced by O. Heaviside
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
Cite This Source Link To impedance
im·ped·ance   (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.

The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Cultural Dictionary

impedance [(im-peed-ns)]

A measure of the apparent resistance posed by an electrical circuit to an alternating current (AC).

Note: The term impedance is most often encountered in dealing with antennas and speakers in television, stereo, and radio systems.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Medical Dictionary

Main Entry: im·ped·ance
Pronunciation: im-'pEd-&n(t)s
Function: noun
1 : the apparent opposition in an electricalcircuit to the flow of an alternating current that is analogous to the actual electrical resistance to a direct current and that is the ratio of effective electromotive force to the effective current
2 : the ratio of the pressure to the volume displacement at a given surface in a sound-transmitting medium
3 : opposition to blood flow in the circulatorysystem
Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.
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Computing Dictionary

impedance electronics, physics
Opposition to flow of alternating current. Impedance consists of resistance plus reactance (capacitive or inductive). Measured in Ohms.
(2003-12-02)

The Free On-line Dictionary of Computing, © 1993-2007 Denis Howe
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