ampere

¹ American  

[am-peer, am-peer] / ˈæm pɪər, æmˈpɪər /

Or ampère

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 American  

[am-peer, ahn-per] / ˈæm pɪər, ɑ̃ˈpɛr /

noun

1. André Marie 1775–1836, French physicist.

---

ampere ¹ British  

/ 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 ^–7 newton 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 British  

/ ˈæmpɛə, ɑ̃pɛr /

noun

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

---

Ampère ¹ Scientific  

/ 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.

---

ampere ² Scientific  

/ 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.

---

Other Word Forms

• Amperian adjective

Etymology

Origin of ampere

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

Example Sentences

An ampere is the flow of one coulomb through an area in one second.

From Textbooks • Aug. 12, 2015

This is the basis of the operational definition of the ampere.

From Textbooks • Aug. 12, 2015

The General Conference on Weights and Measures meets in Sèvres, near Paris, to discuss how to redefine the kilogram, ampere, kelvin and mole.

From Nature • Oct. 12, 2011

A draft resolution to be considered at the General Conference of Weights and Measures in October includes new and improved definitions for the ampere, the mole and the candela.

From New York Times • Feb. 12, 2011

A fraction of an ampere through the human heart muscles can be fatal.

From Electricity for the 4-H Scientist Idaho Agricultural Extension Service Bulletin 396, June, 1962 by Wilson, Eric B.