# User Contributed Dictionary

### Noun

amperes- Plural of ampere

# Extensive Definition

The ampere, in practice often shortened to amp,
(symbol: A) is a unit of electric
current, or amount of electric
charge per second. The ampere is an SI base
unit, and is named after André-Marie
Ampère, one of the main discoverers of electromagnetism.

## Definition

The ampere is a constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed 1 metre apart in a vacuum, would produce between these conductors a force equal to 2×10–7 newton per metre of length. For a description of this force law, see Serway. See also Ampère's force law. The ampere is a base unit, along with the metre, kelvin, second, mole, candela and the kilogram: it is defined without reference to the quantity of electric charge.The unit of charge, the coulomb, is defined to be the
amount of charge displaced by a one ampere current per unit time of
one second. Conversely,
an ampere is one coulomb of charge going past a given point in the
duration of one second; that is, in general, charge Q is determined
by steady current I flowing per unit time t as:

- Q=It \!\

## Realization

The ampere is most accurately realized using a watt balance, but is in practice maintained via Ohm's Law from the units of EMF 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 official realization of a standard ampere is discussed in NIST Special publication 330 Barry N Taylor (editor) Appendix 2, p. 56.## Proposed future definition

Since a coulomb is approximately equal to 6.24150948×1018 elementary charges, one ampere is approximately equivalent to 6.24150948×1018 elementary charges, such as electrons, moving past a boundary in one second.As with other SI base units, there
have been proposals to redefine the kilogram in such a way as to
define some presently measured physical
constants to fixed values. One proposed definition of the
kilogram is:

The kilogram is the mass
which would be accelerated at precisely 2×10-7 m/s2 if subjected to
the per metre force between two straight parallel conductors of
infinite length, of negligible circular cross section, placed 1
metre apart in vacuum, through which flow a constant current of
exactly 6 241 509 479 607 717 888 elementary charges per
second. This redefinition of the kilogram has the effect of
fixing the elementary
charge to be e = 1.60217653 C and would result in a
functionally equivalent definition for the coulomb as being the sum of
exactly 6 241 509 479 607 717 888 elementary charges and the ampere
as being the electrical current of exactly 6 241 509 479 607 717
888 elementary charges per second. This is consistent with the
current 2002 CODATA value for the elementary charge which is
1.60217653×10-19 ± 0.00000014×10-19 C.

### CIPM recommendation

International Committee for Weights and Measures (CIPM) Recommendation 1 (CI-2005): Preparative steps towards new definitions of the kilogram, the ampere, the kelvin and the mole in terms of fundamental constantsThe International Committee for Weights and
Measures (CIPM),

- approve in principle the preparation of new definitions and mises en pratique of the kilogram, the ampere and the kelvin so that if the results of experimental measurements over the next few years are indeed acceptable, all having been agreed with the various Consultative Committees and other relevant bodies, the CIPM can prepare proposals to be put to Member States of the Metre Convention in time for possible adoption by the 24th CGPM in 2011;
- give consideration to the possibility of redefining, at the same time, the mole in terms of a fixed value of the Avogadro constant;
- prepare a Draft Resolution that may be put to the 23rd CGPM in 2007 to alert Member States to these activities;

## See also

## References

## External links

amperes in Arabic: أمبير

amperes in Asturian: Amperiu

amperes in Belarusian: Ампер

amperes in Belarusian (Tarashkevitsa):
Ампэр

amperes in Bengali: অ্যাম্পিয়ার

amperes in Bosnian: Amper

amperes in Breton: Amper

amperes in Bulgarian: Ампер

amperes in Catalan: Ampere

amperes in Czech: Ampér

amperes in Danish: Ampere

amperes in German: Ampere

amperes in Estonian: Amper

amperes in Modern Greek (1453-): Αμπέρ (μονάδα
μέτρησης)

amperes in Spanish: Amperio

amperes in Esperanto: Ampero

amperes in Basque: Anpere

amperes in Persian: آمپر (یکا)

amperes in French: Ampère (unité)

amperes in Friulian: Ampere

amperes in Irish: Aimpéar

amperes in Galician: Ampere

amperes in Korean: 암페어

amperes in Hindi: एम्पीयर

amperes in Croatian: Amper

amperes in Indonesian: Ampere

amperes in Icelandic: Amper

amperes in Italian: Ampere

amperes in Hebrew: אמפר

amperes in Kazakh: Ампер (өлшем бірлік)

amperes in Swahili (macrolanguage): Ampea

amperes in Kurdish: Ampère

amperes in Latvian: Ampērs

amperes in Luxembourgish: Ampere (Eenheet)

amperes in Lithuanian: Amperas

amperes in Hungarian: Amper

amperes in Marathi: अँपियर

amperes in Malay (macrolanguage): Ampere

amperes in Dutch: Ampère

amperes in Japanese: アンペア

amperes in Norwegian: Ampere

amperes in Norwegian Nynorsk: Ampere

amperes in Low German: Ampere

amperes in Polish: Amper

amperes in Portuguese: Ampère

amperes in Romanian: Amper

amperes in Russian: Ампер

amperes in Albanian: Amperimetri

amperes in Simple English: Ampere

amperes in Slovak: Ampér

amperes in Slovenian: Amper

amperes in Serbian: Ампер

amperes in Serbo-Croatian: Amper

amperes in Finnish: Ampeeri

amperes in Swedish: Ampere

amperes in Thai: แอมแปร์

amperes in Vietnamese: Ampe

amperes in Turkish: Amper

amperes in Ukrainian: Ампер

amperes in Chinese: 安培