Siemens (unit) plural. For a conducting element, electrical resistance "R" and electrical conductance "G" are defined as where "I" is the electric current through the object and "V" is the voltage (electrical potential difference) across the object. The unit siemens for the conductance "G" is defined by where Ω is the ohm, A is the ampere, and V is the volt. For a device with a conductance of one siemens, the electric current through the device will increase by one ampere for every increase of one volt of electric potential difference across the device. The conductance of a resistor with a resistance
Electrical resistance and conductance where formula_5 is the length of the conductor, measured in metres [m], "A" is the cross-sectional area of the conductor measured in square metres [m²], σ (sigma) is the electrical conductivity measured in siemens per meter (S·m), and ρ (rho) is the electrical resistivity (also called "specific electrical resistance") of the material, measured in ohm-metres (Ω·m). The resistivity and conductivity are proportionality constants, and therefore depend only on the material the wire is made of, not the geometry of the wire. Resistivity and conductivity are reciprocals: formula_6. Resistivity is a measure of the material's ability to oppose electric current. This