What is hysteresis in electrical terms?

Hysteresis in electrical terms refers to the phenomenon where there is a lag between input and output in a system, often observed in magnetic materials and in certain types of circuits. It is characterized by the dependency of the output on both the current input and the history of the input. Specifically, in the context of magnetic hysteresis, the magnetic flux density does not instantly follow changes in the magnetic field strength; instead, it retains some 'memory' of the past input, resulting in a difference between the magnetization curve going up versus coming down.

This property can lead to current loss as it represents a form of energy dissipation that occurs due to the physical actions being out of phase with the electrical inputs. As materials experience cycles of magnetization, the lagging response can produce losses in the form of heat, which can be considered as 'current loss due to a lag in physical actions.' Hysteresis is critical in the design of various electrical and electronic devices, such as relays, inductors, and transformers, where it influences efficiency and operation.