Hysteresis, pronounced his-stair-e-sis, is the tendency for a system to change or react, sometimes permanently, based on a temporary impact or action. Stemmed from a Greek word meaning "remaining," this phenomenon is used to describe an effect that persists even after the cause is removed.
This term was coined by Sir James Alfred Ewing, a physicist and engineer from Scotland, to describe scientific components that have the function of memory such as elements, magnets and organisms. Now applied to many different fields, hysteresis can refer to the lag time, delay or permanence of an effect after an action. Understanding this phenomenon helps professionals predict the behavior of materials, systems and objects.
Applications of hysteresis
Computing - When added to computer algorithms and user interface (UI) design, hysteresis is used to describe a lagging between the user input and the output. For example, a user might hover over an object that projects a pop-up and the pop-up might stay on the screen for a few seconds even if the user scrolls away. It is also a feature implemented into Amazon Web Services (AWS) Auto Scaling service.
Circuitry - For circuits, a certain amount of hysteresis needs to be added to prevent unsolicited rapid switching. When a person flips a light switch, hysteresis is the property that keeps the switch engaged even when the person has walked away.
Economics - Businesses can experience hysteresis when a previous action predicts future outcomes. This can be seen in periods of high/low unemployment, stock changes, or major investments.
Electric systems - Hysteresis is often implemented in control systems of different appliances/electronics to filter output speed. In thermostats, instead of automatically adjusting the temperature in one burst, the principle of hysteresis slowly makes changes to the environment until the censor detects the desired effect.
Marketing- For marketing professionals, hysteresis can refer to a campaign or promotion that causes a lingering upturn in sales or engagement even when the effort has ended.
Materials - In studying certain fields of materials, hysteresis is when an object is affected by its past state. For example, once a magnet is activated with another magnet, part of their magnetized alignment will remain after being separated. When applied to the pressure inside balloons, the material of the object reacts differently after being blown up or deflated.