Index

## DEFININGCONSTANTSYMBOL: e

**PID**: si:definingconstantsymbol:e:2019**Definition**: The elementary charge,*e*, is exactly 1.602 176 634 × 10^{-19}C.**Source**:*SI Brochure 9th Ed. 2019, p 127***Formatted**:`1.602 176 634 x 10`

^{-19}C**Numerical Value**:*1.602176634E-19***Unit**: C**Unit in Base SI**: A s**Notes**- This value was fixed by the CGPM in 2018 (Resolution 1), with effect from 20 May 2019.
- The elementary charge corresponds to a coupling strength of the electromagnetic force via the fine-structure constant
*α*=*e*^{2}(2*c**ε*_{0}*h*), where*ε*_{0}is the vacuum electric permittivity or electric constant.

**Representations**- Text:
`e`

- HTML:
`<em>e</em>`

- Latex:
`e`

- Text:
**Related Definitions**- isConstantSymbolOf -> elementary charge