Coulomb the volt was defined as the potential difference [i.e., what is nowadays called the "voltage (difference)"] across a conductor when a current of one ampere dissipates one watt of power. The coulomb (later "absolute coulomb" or "abcoulomb" for disambiguation) was part of the EMU system of units. The "international coulomb" based on laboratory specifications for its measurement was introduced by the IEC in 1908. The entire set of "reproducible units" was abandoned in 1948 and the "international coulomb" became the modern Coulomb. The proposed redefinition of the ampere and other SI base units would fix the numerical value of the
Electrical conductor an otherwise-identical short copper wire. The resistance and conductance of a conductor of uniform cross section, therefore, can be computed as where formula_2 is the length of the conductor, measured in metres [m], "A" is the cross-section 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