Preparation for the new SI (kg, h, e, K, V, Ohm, A..) - Page 1
Forum section: electronics / general

author: Dr. Frank
author_rank: Super Contributor
timestamp: October 25, 2018, 07:21:18 pm
content: Everything is ready for the inauguration of the new Système International, the new SI, starting with World Metrology Day, 20th May 2019.https://www.bipm.org/en/measurement-units/rev-si/NIST just announced a live celebration on November 2nd;andhttps://www.nist.gov/si-redefinitionThe bipm, bureau international des poids et mésures, already hosts all draft documents for the new, exact definition of several constants of nature, h, e, k, NA, which will in turn redefine the kg, the Kelvin and the Ampère, and also several derived units, like our beloved Volt and Ohm, which will get exact definitions inside SI, with zero uncertainty.https://www.bipm.org/utils/en/pdf/si-mep/MeP-a-2018.pdfThese two electrical units lived in sin as practical units, since January 1st 1990, when the last SI definition had gone live.From 13th to 16th November 2018, the CGPM, Conférence Générale des Poids et Mesures,https://www.bipm.org/en/cgpm-2018/will meet in Versailles, to officially and ceremonially decide the new SI.The draft documents already contain the finalized values for the mentioned constants of nature, like h, e as derived from many experiments, ending July 1st 2017.These contain thedefintionof the constants and units of the new SI:https://www.bipm.org/utils/en/pdf/CGPM/Convocation-2018.pdfThe mise-en-pratique, or the practical realization also has been prepared, that are the cooking books, how to bring the units to real life.This process is of course not 'exact', as these described experiments inherently have some uncertainties.https://www.bipm.org/en/measurement-units/rev-si/#communicationThere will be a live web cast, obviously during the final decision.FrankPS: Attached the latest version of the mise-en-pratique for the electrical units.

author: branadic
author_rank: Super Contributor
timestamp: November 05, 2018, 06:46:16 pm
content: On 2. november the link to the video showed a new date for the celebration, 5th november 16:00 if I remember right. Now the link to the video has been removed... what's going on? Did they loose their units?-branadic-

author: ataradov
author_rank: Super Contributor
timestamp: November 05, 2018, 07:05:11 pm
content: Why does the document not capitalize units derived from the names? Is it a new thing? Or was it always like that?

author: dacman
author_rank: Frequent Contributor
timestamp: November 06, 2018, 12:44:05 am
content: Units derived from names are capitalized when used as units but not when spelled out in a sentence. For example, the symbol for volts is V and the symbol for ohms is(capital omega). There are exceptions, such as if degrees Celsius is spelled out then Celsius is capitalized (with the excuse that the first letter in degrees is not capitalized). If I were to have 15 Ohm, then I'm technically using units, although I once had an auditor that would tell me ohm is not a unit and should not be capitalized (and I should use the actual symbol because there is a book of what official units are).https://www.bipm.org/en/publications/si-brochure/section5-2.html