hysteresesløyfer

Hysteresesløyfer, also known as hysteresis loops, are graphical representations of the relationship between two physical quantities where the state of the system depends on its history. This phenomenon occurs in various scientific and engineering fields, most notably in magnetism and material science. A hysteresis loop illustrates that the value of one quantity does not solely depend on the current value of the other, but also on whether the other quantity is increasing or decreasing.

In magnetism, a hysteresis loop plots the magnetic flux density (B) against the magnetic field strength (H). When a ferromagnetic material is subjected to a changing magnetic field, its magnetization does not immediately follow the applied field. Instead, it lags behind, forming a loop. This loop shows that even when the external magnetic field is reduced to zero, the material retains some residual magnetization, known as remanence. To demagnetize the material completely, a reverse magnetic field, called the coercivity, must be applied. The area enclosed by the hysteresis loop represents the energy lost as heat during each cycle of magnetization and demagnetization.

Similar hysteresis phenomena can be observed in other systems, such as the stress-strain relationship in elastic materials, where the deformation of the material depends on whether the load is being applied or removed. In the context of electrical components, hysteresis can be found in components like inductors and transformers, affecting their performance under alternating current conditions. Understanding hysteresis loops is crucial for designing and analyzing systems involving magnetic materials, sensors, and memory devices.