The electromagnetic system of units is used to measure electrical quantities of electric charge, current, and voltage, within the centimeter gram second (or "CGS") metric system of units. In electromagnetic units, electric current is derived the CGS base units length, mass, and time by solving Ampere's Law (expressing the force between two parallel conducting wires) for current and setting the constant of proportionality (k_m) equal to unity. Thus, in the CGS-EMU system, electric current is derived from length, mass, and time.
