# impedance

[im-peed-ns]

- 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
- 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.
- something that impedes; an obstacle or hindrance.

## Origin of impedance^{}

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

# impedance

- 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 ohmsSymbol: Z
- a component that offers impedance
- 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 waveSymbol: Z a
- Also called: mechanical impedance the ratio of the mechanical force, acting in the direction of motion, to the velocity of the resulting vibrationSymbol: Z m

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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## Word Origin and History for self-impedance

# impedance

Online Etymology Dictionary, © 2010 Douglas Harper

# impedance

[ĭm-pēd′ns]

- 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. See also impedance matching.

The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

# 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 New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.