Absolute Practical Electrical Units

established for practical electrical measurements by the first International Congress of Electricians (1881) because some electrical units of the cgs absolute electromagnetic system of units were too small or large and therefore inconvenient for practical usage. The units for electrical resistance (ohm) and potential difference (volt) were defined as multiples of the corresponding units in the cgs system (ohm = 10⁹ cgs units and volt = 16⁸ cgs units). The remaining units—the ampere, coulomb, joule, and others—were derived from the ohm and the volt.

Since the 1930’s the absolute units have been part of a system of mechanical, electrical, and magnetic units based on four units (the meter, kilogram, second, and ampere) known as the mksa system of units. Linked with the establishment of the International System of Units (SI) (All-Union State Standard 9867–61) covering all areas of physical and technological measurements, the system of absolute units, together with the mksa system, became a part of the SI and lost its independent status.