ENGLISH
REFERENCE

impedance

n. C / U
C2 Proficiency US //ˌɪmˈpidəns// UK //ɪmpˈiːdəns// im·ped·ance

n. the total resistance that a circuit gives to an electric current. It is like a measure of how much a system slows down the flow of energy.

n. the effective resistance of an electric circuit or component to alternating current, arising from the combined effects of ohmic resistance and reactance. Often used in technical contexts to describe the opposition to energy flow in any physical system.


SIMPLE

The speakers have an impedance of eight ohms.

CONTEXTUAL

Engineers must match the impedance of the transmitter to the antenna to ensure maximum power transfer and signal clarity.

COMPLEX

In high-fidelity audio engineering, maintaining consistent impedance across all components is vital to prevent signal degradation and ensure the accurate reproduction of complex acoustic waveforms.

Synonyms
Origin

From impede + -ance. In sense 2 and sense 3 it was coined by English mathematician and physicist Oliver Heaviside in 1886.

Usage

Uncountable when referring to the general physical property; countable when referring to specific measured values or components.

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