Electrical resistivity and conductivity 1 Ω⋅m. Electrical conductivity or specific conductance is the reciprocal of electrical resistivity, and measures a material's ability to conduct an electric current. It is commonly represented by the Greek letter σ (sigma), but κ (kappa) (especially in electrical engineering) or γ (gamma) are also occasionally used. Its SI unit is siemens per metre (S/m). In an ideal case, cross-section and physical composition of the examined material are uniform across the sample, and the electric field and current density are both parallel and constant everywhere. Many resistors and conductors do in fact have a uniform cross section with a uniform
Armature (electrical) design of the machine and its performance, affecting such factors as commutation in a DC machine or the waveform of an AC machine. Armature wiring is made from copper or aluminum. Copper armature wiring enhances electrical efficiencies due to its higher electrical conductivity. Aluminum armature wiring is lighter and less expensive than copper. Armature (electrical) In electrical engineering, an armature is the power-producing component of an electric machine. The armature can be on either the rotor (rotating part) or the stator (stationary part) of the electric machine. The armature interacts with the magnetic field (magnetic flux) in the air-gap; the