9f7dbe57__units___UK_Metric_Association_SI_base_units_it_measures_and_its_definition
[Unit name] ampere [Symbol] A
Electric current This is the familiar 'amp' we associate with things like fuses and electric cable. It is the fundamental base unit for electricity and magnetism. It is now defined in terms of the magnetic force (induced by the current) exerted between a pair of wires one metre apart. A constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in vacuum, would produce between these conductors a force equal to 2 x 10–7 newton per metre of length. (See section on derived units for a description of the newton.)
Base units | UK Metric Association
What it measures and its definition