Hysteresis

If the input varies from an initial point to a final point and then retraces its value back to the initial point, then the two paths of the output should be identical. If there is hysteresis in the system then the output paths will not coincide.

The stress-strain curve for rubber shows that the behaviour as it is loaded is not the same as when it is unloaded. The curves form a Hysteresis Loop.

Magnetic Hysteresis

The irreversible magnetic flux density versus magnetic field strength (B-versus-H) behaviour found for ferromagnetic and ferrimagnetic materials.

See also: Elastic Hysteresis.