The ampere (symbol: A)'s the SI unit of electric current. The ampere, in practice often shortened to amp,'s an SI base unit, and's named after André-Marie Ampère, one of the main discoverers of electromagnetism. In practical terms, the ampere's a measure of the amount of electric charge passing a point per unit time. Around 6.242 × 1018 electrons passing a given point each second constitutes one ampere. (Since electrons have negative charge, they flow in the opposite direction t… (More on Ampere)