resistance(redirected from threshold resistance)
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resistance, in electricity
resistance, property of an electric conductor by which it opposes a flow of electricity and dissipates electrical energy away from the circuit, usually as heat. Optimum resistance is provided by a conductor that is long, small in cross section, and of a material that conducts poorly. Resistance is basically the same for alternating and direct current circuits (see impedance). However, an alternating current of high frequency tends to travel near the surface of a conductor. Since such a current uses less of the available cross section of the conductor than a direct current, it meets with more resistance than a direct current. In circuit analysis an ideal resistor, i.e., a circuit component whose only property is resistance, is called a resistance. The phenomenon of resistance arises from the interactions of electrons with ions in the conductor. The unit of resistance is the ohm. See superconductivity; Ohm's law; conduction.
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The physical property of a material to resist or impede the conduction of electrical current, measured in ohms. High resistance means poor conductivity and vice versa.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
The opposition that a device or material offers to the flow of direct current, equal to the voltage drop across the element divided by the current through the element. Also known as electrical resistance.
In an alternating-current circuit, the real part of the complex impedance.
In damped harmonic motion, the ratio of the frictional resistive force to the speed. Also known as damping coefficient; damping constant; mechanical resistance.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The physical property of a device, conductor, element, branch, or system, by virtue of which power is lost as heat when current flows through it; the physical property which an electric conductor exhibits to the flow of current; measured in ohms.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
a. the opposition to a flow of electric current through a circuit component, medium, or substance. It is the magnitude of the real part of the impedance and is measured in ohms.
b. (as modifier): resistance coupling
2. any force that tends to retard or oppose motion
3. (in psychoanalytical theory) the tendency of a person to prevent the translation of repressed thoughts and ideas from the unconscious to the conscious and esp to resist the analyst's attempt to bring this about
4. Physics the magnitude of the real part of the acoustic or mechanical impedance
5. See passive resistance
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005