Amp (unit)
See also: Amp, EA
The amp (Symbole has ) is the unit IF of intensity of a Electric current.
This unit owes its name with Andre-Marie Ampère, an outstanding figure which, with Maxwell, contributed to a significant degree to the electromagnetism.
Definition
The definition of the amp was given by the International committee of the weights and measures in 1948.By definition, an amp is the intensity of a constant current which, if it is maintained in two conducting S linear and parallel, of infinite Length S, negligible, and distant sections of a Mètre in the Vide, would produce between these two drivers, a force equalizes with 2×10 -7 newton per linear meter.
Since the international system defines and maintains the tension expressed in Volt and resistance in Ohm with the quantum effects of Josephson (constants of Josephson) (CIPM) (1988). Recommendation 1, statement 56; 19), KJ ≡ 4,835 979×10+14 and of von Klitzing, based on the quantum Hall effect (CIPM (1988), Recommendation 2, statement 56; 20), RK ≡ 2,581 280 7×10+4 Ω), it is possible to combine these values in order to define the amp as being a constant electric current of exactly: 6241509629152650000 elementary charges by second. This last value is the reverse of 1,602×10-19 C, the value of the elementary charge. In fact, there does not exist yet of convincing demonstration of a quantum effect which would make it possible to define the current. Consequently, the metrological triangle (“volt - ohm - amp”) is not buckled.
Multiples of the amp
See too
External bonds
- site BIPM
- @.ampère: Amp and history of electricity, correspondence, works, experiments, films, animations 3D. Site of CNRS realized by the Research center in history of sciences and technology.
Simple: Amp
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