attoampere (aA) One-quintillionth (10-18) of an ampere. The ampere, in practice often shortened to 'amp', (symbol: A) is a unit of electric current, or amount of electric charge per second. The ampere is an SI base unit, and is named after André-Marie Ampère (born, January 22, 1775 Poleymieux, Lyon, France and died June 10, 1836, in Mars...