ampere

¹

or am·père

[ am-peer, am-peer ]

noun

, Electricity.

1. the basic unit of electrical current in the International System of Units (SI), equivalent to one coulomb per second, formally defined to be the constant current which if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed one meter apart in vacuum, would produce between these conductors a force equal to 2 × 10 −7 newton per meter of length. : A, amp.

Ampère

²

[ am-peer; French ahn-per ]

noun

1. An·dré Ma·rie [ahn, -drey m, uh, -, ree, ah, n, -, drey, m, a, -, ree], 1775–1836, French physicist.

ampere

¹

/ ˈæmpɛə /

noun

1. the basic SI unit of electric current; the constant current that, when maintained in two parallel conductors of infinite length and negligible cross section placed 1 metre apart in free space, produces a force of 2 × 10 ^–7newton per metre between them. 1 ampere is equivalent to 1 coulomb per second
2. a former unit of electric current ( international ampere ); the current that, when passed through a solution of silver nitrate, deposits silver at the rate of 0.001118 gram per second. 1 international ampere equals 0.999835 ampere

Ampère

²

/ ˈæmpɛə; ɑ̃pɛr /

noun

1. AmpèreAndré Mari17751836MFrenchSCIENCE: physicistSCIENCE: mathematician André Marie (ɑ̃dre mari). 1775–1836, French physicist and mathematician, who made major discoveries in the fields of magnetism and electricity

ampere

¹

/ ăm′pîr′ /

1. The SI unit used to measure electric current. Electric current through any given cross-section (such as a cross-section of a wire) may be measured as the amount of electrical charge moving through that cross-section in one second. One ampere is equal to a flow of one coulomb per second, or a flow of 6.28 × 10 ¹⁸ electrons per second.

Ampère

²

/ ăm′pîr′,äm-pĕr′ /

1. French mathematician and physicist who is best known for his analysis of the relationship between magnetic force and electric current. He formulated Ampère's law, which describes the strength of the magnetic field produced by the flow of energy through a conductor. The ampere unit of electric current is named for him.

Other Words From

• Am·per·i·an [am-, peer, -ee-, uh, n, -, per, -], adjective

Word History and Origins

Origin of ampere¹

First recorded in 1881; named after A. M. Ampère

Word History and Origins

Origin of ampere¹

C19: named after André Marie Ampère

Example Sentences

New definitions of SI units come into force Revised definitions of four scientific units — the kilogram, the kelvin, the ampere and the mole — came into force on 20 May, World Metrology Day.

From Nature

Revised definitions for four scientific units — the kilogram, the kelvin, the ampere and the mole — come into force today.

From Nature

For example, the resistance per unit length of a channel carrying a current of 1 ampere is about 300 times that of a channel carrying 100 A3.

From Nature

Such a field in turn requires an electrical current of 12,000 amperes.

From New York Times

The four new definitions — for the kilogram, ampere, kelvin and mole — will officially take effect after World Metrology Day, next May 20.

From New York Times