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The ampere (SI unit symbol: A), often shortened to "amp",〔SI supports only the use of symbols and deprecates the use of abbreviations for units.〕 is the SI unit of electric current〔(Base unit definitions: Ampere ). Physics.nist.gov. Retrieved on 2010-09-28.〕 (dimension symbol: I) and is one of the seven〔The other six are the metre, kelvin, second, mole, candela, and kilogram〕 SI base units. It is named after André-Marie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics. The ampere is equivalent to one coulomb (roughly times the elementary charge) per second. Amperes are used to express flow rate of electric charge. For any point experiencing a current, if the number of charged particles passing or the charge on the particles is increased, the amperes of current at that point will proportionately increase. The ampere should not be confused with the coulomb (also called "ampere-second") or the ampere-hour (A⋅h). The ampere is a unit of current, the amount of charge transiting per unit time, and the coulomb is a unit of charge. When SI units are used, constant, instantaneous and average current are expressed in amperes (as in "the charging current is 1.2 A") and the charge accumulated, or passed through a circuit over a period of time is expressed in coulombs (as in "the battery charge is "). The relation of the ampere to the coulomb is the same as that of the watt to the joule, and that of metre per second to metre. ==Definition== Ampère's force law〔.〕 states that there is an attractive or repulsive force between two parallel wires carrying an electric current. This force is used in the formal definition of the ampere, which states that the ampere is the constant current that will produce an attractive force of 2 × 10−7 newtons per metre of length between two straight, parallel conductors of infinite length and negligible circular cross section placed one metre apart in a vacuum.〔〔.〕 The SI unit of charge, the coulomb, "is the quantity of electricity carried in 1 second by a current of 1 ampere".〔.〕 Conversely, a current of one ampere is one coulomb of charge going past a given point per second: : In general, charge ''Q'' is determined by steady current ''I'' flowing for a time ''t'' as . 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ampere」の詳細全文を読む スポンサード リンク
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