impedance

[ im-peed-ns ]
/ ɪmˈpid ns /

noun

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

1886; impede + -ance; term introduced by O. Heaviside

OTHER WORDS FROM impedance

self-im·ped·ance, noun

Example sentences from the Web for impedance

British Dictionary definitions for impedance

impedance
/ (ɪmˈpiːdəns) /

noun

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
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 wave Symbol: Z a
Also called: mechanical impedance the ratio of the mechanical force, acting in the direction of motion, to the velocity of the resulting vibration Symbol: Z m

Scientific definitions for impedance

impedance
[ ĭm-pēdns ]

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.

Cultural definitions for impedance

impedance
[ (im-peed-ns) ]

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

notes for impedance

The term impedance is most often encountered in dealing with antennas and speakers in television, stereo, and radio systems.