Thursday, 22 January 2015

The Electrical Resistivity


The electrical resistivity of the electrical resistivity of matter is made of a cube with sides equal to one (1 meter) when the current goes perpendicular to its two opposite faces, an area of 1 square meter each.

The resistivity depends on the concentration of free electrons in the conductor and the distance between the ions of the crystal lattice, in other words, the material of the conductor.
The dimension of the electrical resistivity in SI (International System of Units, Eng. - International System of Units) - Ohm-m [Ohm * m ^ 2 / m] (SI - Ω • m, Rus. - Ohm meter, Eng. - Ohm-meter).

 For the measurement of electrically conductive materials may be used non-SI units - Ohm mm2 / m (for millimeter-section of a conductor length of 1 m., That is - millionth of a meter-ohms).

The physical meaning of the resistivity: material (homogeneous and isotropic *) has the electrical resistivity of one ohm-m, if made of this material is a cube with sides of 1 meter has a resistance of 1 ohm when measured on the opposite faces of the cube.