Hysteresis
![Electric displacement field D of a ferroelectric material as the electric field E is first decreased, then increased. The curves form a hysteresis loop.](/Images/godic/202501/19/Ehysteresis2116.PNG")
![Sharp hysteresis loop of a Schmitt trigger](/Images/godic/202501/19/Hysteresis_sharp_curve.svg2116.png")
![Elastic hysteresis of an idealized rubber band. The area in the centre of the hysteresis loop is the energy dissipated due to internal friction.](/Images/godic/202501/19/Elastic_Hysteresis.svg2116.png")
![Theoretical model of magnetization m against magnetic field h. Starting at the origin, the upward curve is the initial magnetization curve. The downward curve after saturation, along with the lower return curve, form the main loop. The intercepts hc and mrs are the coercivity and saturation remanence.](/Images/godic/202501/19/StonerWohlfarthMainLoop.svg2116.png")
Hysteresis is the time-based dependence of a system's output on present and past inputs. The dependence arises because the history affects the value of an internal state. To predict its future outputs, either its internal state or its history must be known. If a given input alternately increases and decreases, a typical mark of hysteresis is that the output forms a loop as in the figure.