# What is the SI unit of inductance

## Henry (unit)

Henry is the SI unit of inductance. The unit is named after Joseph Henry. It is specific to each conductor coil and is usually indicated on it.

A coil has an inductance of 1 henry if a self-induction voltage of 1 volt is produced with a uniform current change of 1 ampere in 1 second.

### CGS system of units

The Abhenry (abH) is the outdated unit of measurement for inductance from the electromagnetic CGS system of units. It applies

1 abH = 10−9 H = 1 nH (nanohenry)

In an inductance of 1 abH, a current increasing by 1 Abampere per second generates a voltage of 1 Abvolt.

The Stathenry (statH) is the outdated unit of measurement for inductance from the electrostatic CGS system of units. It applies

1 statH = c2 × 10−5 H ~ 8.99 × 1011 H = 899 GH (gigahenry)

In an inductance of 1 statH, a current increasing by 1 statampere per second generates a voltage of 1 statvolt.

Before the introduction of the SI, today's SI-Henry was called absolute Henry whereas Henry, derived from the definition of the (international) ohm at the time, is called international henry. Since the national standard authorities have determined different conversion factors based on the measurement regulations of the definitions, there have been nationally different numerical values ​​for the international Henry. In 1946 the International Committee for Weights and Measures determined the mean international ohm to be 1,00049 Ω, which also applies:

1 medium international henry = 1 H.int = 1,00049 H.

The American international Henry was also significant:

1 US International Henry = 1,000495 H