Electrical resistance and conductance

relationship between voltage and current across an ideal resistor

material whose internal electric charges do not flow freely, and which therefore does not conduct an electric current

quotient of the voltage phasor and the electric current phasor

a circuit element's opposition to changes in electric current due to its inductance or capacitance

thumb|An analog ohmmeter

In electrical engineering, admittance is a measure of how easily a circuit or device will allow a current to flow. It is defined as the reciprocal of impedance, analogous to how conductance and resistance are defined. The SI unit of admittance is the siemens (symbol S); the older, synonymous unit is mho, and its symbol is ℧ (an upside-down uppercase omega Ω). Oliver Heaviside coined the term admittance in December 1887. Heaviside used to represent the magnitude of admittance, but it quickly became the conventional symbol for admittance itself through the publications of Charles Proteus Steinme

law of physics

current output as a function of applied voltage for a material or device

measure of a substance's ability to resist or conduct electric current

impedance of a linear circuit's Thévenin representation

opposition to the passage of an electric current

describes the scattering of conduction electrons in a metal due to magnetic impurities, resulting in a characteristic change in electrical resistivity with temperature

Transconductance (for transfer conductance), also infrequently called mutual conductance, is the electrical characteristic relating the current through the output of a device to the voltage across the input of a device. Conductance is the reciprocal of resistance.

electrical resistance for current flowing across a pair of electrical contacts

measure of electrical resistance of a thin film of uniform thickness

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