Author Topic: Changing to the 2019 SI Redefinitions on May-20  (Read 731 times)

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Offline Magnificent Bastard

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Changing to the 2019 SI Redefinitions on May-20
« on: May 17, 2019, 05:32:37 pm »
This post was stolen from:  Changing to the 2019 SI Redefinitions

On May 20, 2019 new values will be implemented for the International System of Units (SI) base units of the kilogram, Kelvin, mole and ampere, and the derived units of the volt and ohm. These values are based on redefinitions of the Planck constant, elementary charge, the Boltzmann constant and the Avogadro constant. The changes are based on the evolution of the definition of the kilogram, which has progressed from a physical artifact—held at the International Bureau of Weight and Measures (BIPM) since 1889—to a constant of nature, Planck’s constant, that can be accessed anywhere in the universe. This change benefits the entire world in potentially having better access to realization of the kilogram, and eliminates the risks associated with maintaining a standard that is based on a sole artifact. As a result of the redefinitions, some measurement reference standards must be adjusted to the new value of the definition. Other measurement reference standards may account for the redefined value by incorporating an additional contributor to their measurement uncertainty evaluations. The attached application note summarizes the changes being made and provides guidance on how to implement them.
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Offline mzzj

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Re: Changing to the 2019 SI Redefinitions on May-20
« Reply #1 on: May 18, 2019, 11:06:58 am »
"The International Committee of Weights and
Measures (CIPM) Consultative Committee on Electromagnetic Quantities (CCEM) has produced a
guideline which states that no action is required
if your voltage related uncertainties are larger
than 0.25 ppm5. If your uncertainty for the volt
is less than 0.25 ppm and you do not have direct
access to a JVS, we recommend that you add the
0.107 ppm adjustment quantity to your uncertainty analysis."

Unfortunately I don't have any voltage standards with calibration uncertainties below 0.25ppm  :P

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