# henry (H)

The Henry (H) is the unit for inductance. It is a unit from the System of Units (SI) named after the American physicist Joseph Henry (1797 to 1878) and is expressed in volt-seconds per ampere

(Vs/A), which is equivalent to ohm-seconds.

An inductance of 1 Henry produces a self-inductance of 1 volt (V) in a coil when the current changes at a uniform rate of 1 ampere (A) in one second (s). Coil sizes are given prefixes, so there is the milli-henry (mH), the micro-henry (µH), the nano-henry (nH), etc.