## Ampere |

Ampere | |
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Demonstration model of a moving iron | |

General information | |

Unit of | |

Symbol | A |

Named after |

The **ampere** (^{[1]}^{[2]} symbol: **A**),^{[3]} often ^{[4]} is the ^{[5]}^{[6]} It is named after

The International System of Units defines the ampere in terms of other base units by measuring the electromagnetic force between electrical conductors carrying electric current. The earlier ^{[7]} In SI, the unit of charge, the coulomb, is defined as the charge carried by one ampere during one second.

^{[8]}

The ampere is defined by taking the fixed numerical value of the *e* to be 1.602 176 634 × 10^{−19} when expressed in the unit C, which is equal to A s, where the second is defined in terms of ∆*ν _{Cs}*, the unperturbed ground state hyperfine transition frequency of the caesium-133 atom.

The SI unit of charge, the ^{[10]} 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 *Q* = *It*.

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