OurBigBook.com $£ Sponsor 中国独裁统治 China Dictatorship 新疆改造中心、六四事件、法轮功、郝海东、709大抓捕、2015巴拿马文件邓家贵、低端人口、西藏骚乱

Ampere in the 2019 redefinition of the SI base units

TODO how does basing it on the elementary charge help at all? Can we count individual electrons going through a wire? www.nist.gov/si-redefinition/ampere/ampere-quantum-metrology-triangle by the NIST explains that is it basically due to the following two quantized solid-state physics phenomena/experiments that allows for extremely precise measurements of the elementary charge:

quantum Hall effect, which has discrete resistances of type:
$R_{x y} = \frac{V _{Hall}}{I _{channel}} = \frac{h}{e ^{2} ν}$
(1)
for integer values of $ν$ .
Josephson effect, which provides the Josephson constant which equals:
$K_{J} = \frac{2 e}{h}$
(2)

 Ancestors (9)

 Incoming links (4)