Impedance is the complex-valued generalization of
resistance. It may refer to:
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Acoustic impedance
Acoustic impedance and specific acoustic impedance are measures of the opposition that a system presents to the acoustic flow resulting from an acoustic pressure applied to the system. The International System of Units, SI unit of acoustic impeda ...
, a constant related to the propagation of sound waves in an acoustic medium
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Electrical impedance
In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of Electrical_resistance, resistance and Electrical_reactance, reactance in a electrical circuit, circuit.
Quantitatively, the impedan ...
, the ratio of the voltage phasor to the electric current phasor, a measure of the opposition to time-varying electric current in an electric circuit
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High impedance, when only a small amount of current is allowed through
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Characteristic impedance of a transmission line
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Impedance (accelerator physics), a characterization of the self interaction of a charged particle beam
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Nominal impedance, approximate designed impedance
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Impedance matching
In electrical engineering, impedance matching is the practice of designing or adjusting the input impedance or output impedance of an electrical device for a desired value. Often, the desired value is selected to maximize power transfer or ...
, the adjustment of input impedance and output impedance
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Mechanical impedance, a measure of opposition to motion of a structure subjected to a force
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Wave impedance, a constant related to electromagnetic wave propagation in a medium
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Impedance of free space, a universal constant and the simplest case of a wave impedance
See also
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