Ampere
In physics, the ampere (symbol: A, often informally abbreviated to amp) is the SI base unit used to measure electrical currentss. By definition, 1 ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2x10-7 newton per meter of length.
The ampere is named after André-Marie Ampère, one of the main discoverers of electromagnetism.
The unit of electric charge, the coulomb, is defined in terms of the ampere: 1 coulomb is the amount of electric charge carried in a current of 1 ampere flowing for 1 second. (By SI standards, 1 coulomb per second is actually equal to 0.999835 ampere.)
