hysterézní

Hysterézní refers to the phenomenon where the output of a system depends not only on its current input but also on its past inputs. This means the system exhibits a "memory" and its response to a given input will differ depending on whether the input is increasing or decreasing. This behavior is often represented by a hysteresis loop when plotting the output against the input.

In physics and engineering, hysteresis is commonly observed in magnetic materials. When a magnetic field is applied to a ferromagnetic material, it becomes magnetized. As the magnetic field is increased, the magnetization also increases. However, when the magnetic field is decreased, the magnetization does not follow the same path. It remains at a certain level even when the magnetic field is zero, a phenomenon known as remanence. To demagnetize the material completely, a magnetic field in the opposite direction must be applied. This irreversible behavior forms the characteristic hysteresis loop.

Hysteresis is also found in other systems, such as mechanical springs, where the stress-strain relationship can be different during loading and unloading. In electrical components like relays and Schmitt triggers, hysteresis is intentionally designed to provide noise immunity and prevent rapid switching. In economics, hysteresis can describe situations where a temporary shock has a long-lasting effect on economic variables, such as unemployment. The presence of hysteresis implies that the system's state is not solely determined by the instantaneous input but is also influenced by its history.