This page documents an OPTIMADE Unit Definition. See https://schemas.optimade.org/ for more information.

**ID: https://schemas.optimade.org/defs/v1.2/units/si/1960/base/ampere**

`ampere`

**Unit name:** ampere

**Latin symbol:** A

**Display symbol:** A

**Description:** The SI base unit of electric current defined from the force between parallel wires carrying an electric current, which was included in the SI at the 11th CGPM Meeting in 1960.

"The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2×10⁻⁷ MKS unit of force per metre of length." [41st CIPM meeting (1946), Resolution 2]. The ampere was adopted into SI at the 11th CGPM Meeting in 1960, resolution 12.

Furthermore, the SI 1960 definition of the ampere depend on:

- the SI 1960 metre (https://schemas.optimade.org/defs/v1.2/units/si/1960/base/metre)
- the MKS unit of force, which references the derived SI unit newton (https://schemas.optimade.org/defs/v1.2/units/si/1960/derived/newton) equal to kilogram·metre·second⁻², referencing the SI 1960 kilogram (https://schemas.optimade.org/defs/v1.2/units/si/1960/base/kilogram), metre (https://schemas.optimade.org/defs/v1.2/units/si/1960/base/metre) and second (https://schemas.optimade.org/defs/v1.2/units/si/1960/base/second).

**Resources:**

- Definition at the 41st CIPM meeting (1946), resolution 2
- Establishment of the SI unit system at the 11th CGPM meeting (1960), resolution 12.
- Wikipedia article describing the unit

**JSON definition:**

```
{
"$id": "https://schemas.optimade.org/defs/v1.2/units/si/1960/base/ampere",
"$schema": "https://schemas.optimade.org/meta/v1.2/optimade/physical_unit_definition.json",
"title": "ampere",
"symbol": "A",
"display-symbol": "A",
"description": "The SI base unit of electric current defined from the force between parallel wires carrying an electric current, which was included in the SI at the 11th CGPM Meeting in 1960.\n\n\"The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2\u00d710\u207b\u2077 MKS unit of force per metre of length.\" [41st CIPM meeting (1946), Resolution 2].\nThe ampere was adopted into SI at the 11th CGPM Meeting in 1960, resolution 12.\n\nFurthermore, the SI 1960 definition of the ampere depend on:\n\n- the SI 1960 metre (https://schemas.optimade.org/defs/v1.2/units/si/1960/base/metre)\n- the MKS unit of force, which references the derived SI unit newton (https://schemas.optimade.org/defs/v1.2/units/si/1960/derived/newton) equal to kilogram\u00b7metre\u00b7second\u207b\u00b2, referencing the SI 1960 kilogram (https://schemas.optimade.org/defs/v1.2/units/si/1960/base/kilogram), metre (https://schemas.optimade.org/defs/v1.2/units/si/1960/base/metre) and second (https://schemas.optimade.org/defs/v1.2/units/si/1960/base/second).",
"resources": [
{
"relation": "Definition at the 41st CIPM meeting (1946), resolution 2",
"resource-id": "https://www.bipm.org/en/committees/ci/cipm/41-1946/resolution-2"
},
{
"relation": "Establishment of the SI unit system at the 11th CGPM meeting (1960), resolution 12.",
"resource-id": "https://www.bipm.org/en/committees/cg/cgpm/11-1960/resolution-12"
},
{
"relation": "Wikipedia article describing the unit",
"resource-id": "https://en.wikipedia.org/wiki/Ampere"
}
],
"standard": {
"name": "si",
"year": 1960,
"category": "base",
"symbol": "A"
},
"x-optimade-definition": {
"label": "ampere_si_1960_base",
"kind": "unit",
"format": "1.2",
"version": "1.2.0",
"name": "ampere"
}
}
```