A

David

Darling

ampere

The ampere is the base unit of electric current in the SI system. One ampere (A), or amp, is defined as the constant current that, if maintained in two straight parallel conductors of infinite length and negligible circular cross-section, and placed 1 meter apart in vacuum, would produce between these conductors a force of 2 10-7 newton per meter. It is named after the French physicist André Marie Ampère.