the ohm, the volt, the ampere and others, established for practical electrical measurements by the 1st International Congress of Electricians (1881). They replaced the electrical units of the CGS system of units, since some of those units were too small or too large and therefore inconvenient in practical use. The unit of electrical resistance (the ohm) and the unit of potential difference (the volt) were established as multiples of the corresponding CGS units (1 Ω=109 CGS units, 1 V=108 CGS units). The remaining units — the ampere, the coulomb, the joule and others — were derived from the ohm and the volt. Later the absolute practical electrical units were included in the MKSA system of units, in which the ampere was adopted as the base unit. When the International System of Units (SI) was established, covering every field of physical and technical measurement, the absolute practical electrical units entered SI together with the MKSA system.