The SI unit of charge, the coulomb, " is the quantity of electricity carried in 1 second by a current of 1 ampere ".

The SI unit of measurement of electric current, the ampere, is named after him.

The SI unit for measuring the rate of flow of electric charge is the ampere, which is charge flowing through some surface at the rate of one coulomb per second.

Electromagnetic units are part of a system of electrical units based primarily upon the magnetic properties of electric currents, the fundamental SI unit being the ampere.

In the SI system, the coulomb is defined in terms of the ampere and second: 1C = 1A × 1s.

For example, one possible proposed redefinition is " the ampere ... is such that the value of the elementary charge e ( charge on a proton ) is exactly 1. 602176487 × 10 < sup >− 19 </ sup > coulomb " This proposal is not yet accepted as part of the SI system: The SI definitions are unlikely to change until at least 2015.

Constants c < sub > 0 </ sub > and μ < sub > 0 </ sub > are defined in SI units to have exact numerical values, shifting responsibility of experiment to the determination of the meter and the ampere.

In the SI system, ampere per meter ( A / m ) is used for H-field and tesla is used for B-field.

The Oersted is 1000 / 4π (≈ 79. 5774715 ) ampere per meter, in terms of SI units.

In the SI system, there are seven fundamental units: kilogram, meter, candela, second, ampere, kelvin, and mole.

* See ampere for Giga-ampere ( GA ) or Gigampere, an SI unit of electric current ( equals 1, 000, 000, 000 A ).

In the table below are listed all conversion factors that are useful to convert between all combinations of the SI base units, and if not possible, between them and their unique elements, because ampere is a dimensionless ratio of two lengths such as, and candela ( 1 / 683 ) is a dimensionless ratio of two dimensionless ratios such as ratio of two volumes = and ratio of two areas =, while mole is only a dimensionless Avogadro number of entities such as atoms or particles:

Magnetomotive force ( MMF ) or magnetomotance ( SI Unit: Ampere ), represented by a steady, direct electric current of one ampere flowing in a single-turn loop of electrically conducting material in a vacuum.

The conversion factor between the SI and CGS units is (≈ 0. 795774715 ) ampere for every gilbert.

The unit is still often described as ampere-turns, since the value in SI units ( ampere ) is the product of the current in a coil times the number of turns of the coil that contribute to the total magnetomotance.

The old unit of conductance, the mho ( ohm spelled backwards ), was replaced by the SI ( International System ) unit, the siemens, with the symbol S ( 1 siemens = 1 ampere per volt ).

The ampere balance ( also current balance or Kelvin balance ) is an electromechanical apparatus used for the precise measurement of the SI unit of electric current, the ampere.

In SI units, permeability is measured in henrys per meter ( H · m < sup >− 1 </ sup >), or newtons per ampere squared ( N · A < sup >− 2 </ sup >).

In SI, a separate base unit ( the ampere ) is associated with electrical phenomena, with the consequence that something like electrical charge ( 1 coulomb = 1 ampere × 1 second ) is a unique dimension of physical quantity and is not expressed purely in terms of the mechanical units ( kilogram, metre, second ).

In practical terms, the ampere is a measure of the amount of electric charge passing a point in an electric circuit per unit time with 6. 241 × 10 < sup > 18 </ sup > electrons, or one coulomb per second constituting one ampere.

Illustration of the definition of the ampere unit

The ampere was originally defined as one tenth of the CGS system electromagnetic unit of current ( now known as the abampere ), the amount of current that generates a force of two dynes per centimetre of length between two wires one centimetre apart.

In recognition of his contribution to the creation of modern electrical science, an international convention signed in 1881 established the ampere as a standard unit of electrical measurement, along with the coulomb, volt, ohm, and watt, which are named, respectively, after Ampère ’ s contemporaries Charles-Augustin de Coulomb of France, Alessandro Volta of Italy, Georg Ohm of Germany, and James Watt of Scotland.

According to the centimeter gram second system of units ( cgs ), the gauss is the unit of magnetic field B and the equivalent of esu / cm ^ 2, while the oersted is the unit of magnetizing field H. One tesla is equal to 10 < sup > 4 </ sup > gauss, and one ampere per meter is equal to 4π × 10 < sup >− 3 </ sup > oersted.

File: Andre-marie-ampere2. jpg | André-Marie Ampère ( 1777-1836 ): main founder of electrodynamics, showed how an electric current produces a magnetic field, stated that the mutual action of two lengths of current-carrying wire is proportional to their lengths and to the intensities of their currents ( Ampère's law ), namesake of the unit of electric current ( the ampere )

* André-Marie Ampère ( 1775 – 1836 ), physicist ( namesake of electrical unit ampere )

The ampere-turn ( AT ) was the MKS unit of magnetomotive force ( MMF ), represented by a direct current of one ampere flowing in a single-turn loop in a vacuum.

The gilbert is defined differently, and is a slightly smaller unit than the ampere.

This group also recognized that any one of the practical units already in use ( ohm, ampere, volt, henry, farad, coulomb, and weber ), could equally serve as the fourth fundamental unit.

" After consultation, the ampere was adopted as the fourth unit of the Giorgi system in Paris in 1950.

Since a coulomb is approximately equal to elementary charges ( such as electrons ), one ampere is approximately equivalent to elementary charges moving past a boundary in one second, or the reciprocal of the value of the elementary charges in coulombs.

It is equal to the energy expended ( or work done ) in applying a force of one newton through a distance of one metre ( 1 newton metre or N · m ), or in passing an electric current of one ampere through a resistance of one ohm for one second.

Under a light load ( 0. 5 ampere ), the starting voltage of a freshly charged AA NiMH cell in good condition is about 1. 4 volts ; This voltage falls rapidly to about 1. 25 volts at 10 % depth of discharge ( DOD ) and then remains almost constant until the cell is over 80 % discharged.

Instead, the ampere figure is preceded by a letter " B ", " C " or " D " that indicates the instantaneous tripping current, that is the minimum value of current that causes the circuit-breaker to trip without intentional time delay ( i. e., in less than 100 ms ), expressed in terms of I < sub > n </ sub >:

The weber is commonly expressed in terms of other derived units as the Tesla-square meter ( T · m < sup > 2 </ sup >), volt-seconds ( V · s ), or joules per ampere ( J / A ).

However, aside from a bundled 2. 5 ampere C64 power supply unit ( the factory unit could not support the 1764 ), there were only minor differences between the three models.

The unit of magnetomotive force is the ampere-turn ( At ), represented by a steady, direct electric current of one ampere flowing in a single-turn loop of electrically conducting material in a vacuum.

This force is used in the formal definition of the ampere, which states that it is " the constant current that will produce an attractive force of 2 × 10 < sup >– 7 </ sup > newton per metre of length between two straight, parallel conductors of infinite length and negligible circular cross section placed one metre apart in a vacuum ".

Conversely, a current of one ampere is one coulomb of charge going past a given point per second:

The standard ampere is most accurately realized using a watt balance, but is in practice maintained via Ohm's Law from the units of electromotive force and resistance, the volt and the ohm, since the latter two can be tied to physical phenomena that are relatively easy to reproduce, the Josephson junction and the quantum Hall effect, respectively.

The interaction is mediated by the magnetic field each current produces and forms the basis for the international definition of the ampere.

One henry is the inductance that will induce a potential difference of one volt if the current through it changes at a rate of one ampere per second.

The coulomb is defined as the quantity of charge that has passed through the cross section of an electrical conductor carrying one ampere within one second.

An ohm is equivalent to a volt per ampere.