# Dictionary Definition

ampere

### Noun

1 a former unit of electric current (slightly
smaller than the SI ampere) [syn: international
ampere]

2 the basic unit of electric current adopted
under the Systeme International d'Unites; "a typical household
circuit carries 15 to 50 amps" [syn: amp, A]

# User Contributed Dictionary

## English

### Etymology

Named after the French phyicist Ampère.### Pronunciation

### Noun

ampere (plural amperes)- a unit of electrical current, the standard base unit
in the
International System of Units. Abbreviation: amp, Symbol: A
- Definition: ''The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2 x 10–7 newton per metre of length.'' (The International Bureau of Weights and Measures)

#### Translations

- Croatian: amper
- Finnish: ampeeri
- French: ampère
- German: Ampere
- Greek: αμπέρ (ambér)
- Italian: ampere (p: ampere)
- Polish: amper
- Russian: ампер (ampér)
- Swedish: ampere

## Italian

### Noun

ampere m inv#### Related terms

# 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

ampere in Arabic: أمبير

ampere in Asturian: Amperiu

ampere in Belarusian: Ампер

ampere in Belarusian (Tarashkevitsa):
Ампэр

ampere in Bengali: অ্যাম্পিয়ার

ampere in Bosnian: Amper

ampere in Breton: Amper

ampere in Bulgarian: Ампер

ampere in Catalan: Ampere

ampere in Czech: Ampér

ampere in Danish: Ampere

ampere in German: Ampere

ampere in Estonian: Amper

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

ampere in Spanish: Amperio

ampere in Esperanto: Ampero

ampere in Basque: Anpere

ampere in Persian: آمپر (یکا)

ampere in French: Ampère (unité)

ampere in Friulian: Ampere

ampere in Irish: Aimpéar

ampere in Galician: Ampere

ampere in Korean: 암페어

ampere in Hindi: एम्पीयर

ampere in Croatian: Amper

ampere in Indonesian: Ampere

ampere in Icelandic: Amper

ampere in Italian: Ampere

ampere in Hebrew: אמפר

ampere in Kazakh: Ампер (өлшем бірлік)

ampere in Swahili (macrolanguage): Ampea

ampere in Kurdish: Ampère

ampere in Latvian: Ampērs

ampere in Luxembourgish: Ampere (Eenheet)

ampere in Lithuanian: Amperas

ampere in Hungarian: Amper

ampere in Marathi: अँपियर

ampere in Malay (macrolanguage): Ampere

ampere in Dutch: Ampère

ampere in Japanese: アンペア

ampere in Norwegian: Ampere

ampere in Norwegian Nynorsk: Ampere

ampere in Low German: Ampere

ampere in Polish: Amper

ampere in Portuguese: Ampère

ampere in Romanian: Amper

ampere in Russian: Ампер

ampere in Albanian: Amperimetri

ampere in Simple English: Ampere

ampere in Slovak: Ampér

ampere in Slovenian: Amper

ampere in Serbian: Ампер

ampere in Serbo-Croatian: Amper

ampere in Finnish: Ampeeri

ampere in Swedish: Ampere

ampere in Thai: แอมแปร์

ampere in Vietnamese: Ampe

ampere in Turkish: Amper

ampere in Ukrainian: Ампер

ampere in Chinese: 安培