|abampere or biot|
|Unit of||electric current|
|Symbol||abA or Bi|
|Named after||A.-M. Ampère or J.-B. Biot|
|In CGS base units||g1/2⋅cm1/2⋅s−1 :25|
|1 abA in ...||... corresponds to ...|
|SI base units||10 amperes:25|
|CGS-ESU||ccgs statamperes[Note 1] ≈2.9979×1010 statamperes:16|
The abampere (abA), also called the biot (Bi) after Jean-Baptiste Biot, is the derived electromagnetic unit of electric current in the emu-cgs system of units (electromagnetic cgs). One abampere corresponds to ten amperes in the SI system of units. An abampere of current in a circular path of one centimeter radius produces a magnetic field of 2π oersteds at the center of the circle.
The name abampere was introduced by Kennelly in 1903 as a short name for the long name (absolute) electromagnetic cgs unit of current that was in use since the adoption of the cgs system in 1875. The abampere was coherent with the emu-cgs system, in contrast to the ampere, the practical unit of current that had been adopted too in 1875.
The emu-cgs (or "electromagnetic cgs") units are one of several systems of electromagnetic units within the centimetre–gram–second system of units; others include esu-cgs, Gaussian units, and Lorentz–Heaviside units. In these other systems, the abampere is not one of the units; the "statcoulomb per second" or statampere is used instead.
The other units in this system related to the abampere are: