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Ohm's law states that the electric current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, [1] one arrives at the three mathematical equations used to describe this relationship: [2] where I is the current through the conductor, V ...
The SI unit of electrical resistivity is the ohm - metre (Ω⋅m). [1][2][3] For example, if a 1 m3 solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is 1 Ω, then the resistivity of the material is 1 Ω⋅m. Electrical conductivity (or specific conductance) is the reciprocal of ...
Ohm's law is satisfied when the graph is a straight line through the origin. Therefore, the two resistors are ohmic, but the diode and battery are not. For many materials, the current I through the material is proportional to the voltage V applied across it: over a wide range of voltages and currents. Therefore, the resistance and conductance ...
The formula is a combination of Ohm's law and Joule's law: = = =, where P is the power, R is the resistance, V is the voltage across the resistor, and I is the current through the resistor. A linear resistor has a constant resistance value over all applied voltages or currents; many practical resistors are linear over a useful range of currents.
Electric current. A simple electric circuit, where current is represented by the letter i. The relationship between the voltage (V), resistance (R), and current (i or I) is V=IR; this is known as Ohm's law. Common symbols. I.
For example, a 10 ohm resistor connected in parallel with a 5 ohm resistor and a 15 ohm resistor produces 1 / 1/10 + 1/5 + 1/15 ohms of resistance, or 30 / 11 = 2.727 ohms. A resistor network that is a combination of parallel and series connections can be broken up into smaller parts that are either one or the other.
Drude model. The Drude model of electrical conduction was proposed in 1900 [1][2] by Paul Drude to explain the transport properties of electrons in materials (especially metals). Basically, Ohm's law was well established and stated that the current J and voltage V driving the current are related to the resistance R of the material.
As originally stated in terms of direct-current resistive circuits only, Thévenin's theorem states that "Any linear electrical network containing only voltage sources, current sources and resistances can be replaced at terminals A–B by an equivalent combination of a voltage source Vth in a series connection with a resistance Rth."