The unit of inductance is the henry (H), and it is named after Joseph Henry, an American scientist who made significant contributions to the study of electromagnetism. One henry (1 H) is defined as the inductance of a coil when an electromotive force (EMF) of one volt is induced in the coil by a rate of change of current of one ampere per second. In other words, it is the inductance that results in an EMF of one volt when the current through the coil changes at a rate of one ampere per second.