resistance
The degree to which a substance or device opposes the passage of an electric current, causing energy to be dissipated as heat.
In electrical terms, resistance is a constant property of DC circuits (and AC circuits with only resistive loads), unlike impedance, which changes with frequency.
Word relationships
- opposition: Opposition is a general term for any force that fights another, while resistance is the specific physical property that opposes electrical current.
- conductance: Conductance is the ease with which an electric current passes through a material, mathematically the reciprocal of resistance.
Commonly confused with
- impedance: Resistance opposes current in both AC and DC circuits and does not vary with frequency, whereas impedance is the total opposition in AC circuits, combining resistance and reactance.
Word family
- resist (verb): To oppose or withstand.
- resistor (noun): A passive electrical component designed to introduce resistance into a circuit.
- resistive (adjective): Tending to resist; having electrical resistance.
Collocations
- electrical resistance
- internal resistance
- high resistance
- measure resistance
Idioms & expressions
- path of least resistance
Example sentences
- "The heating element in a toaster relies on high resistance to convert electrical energy into warmth." Explaining the heat generated by home appliances.
- "We find that the resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area." A foundational text on electrical circuits.
Memory hook
Imagine a crowd of people trying to run down a narrow hallway; the narrow walls act as a 'resistance' that slows them down. Resistance stands against the flow.
When not to use
Do not use resistance when discussing alternating current systems where frequency-dependent opposition (impedance) is the dominant factor.
Fun facts
- When certain materials are cooled to near absolute zero, their electrical resistance drops to exactly zero, a phenomenon known as superconductivity.
Explore more words
impedance, conductivity, stability, Mass, attenuation, resonance
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