There is a certain level specific to every core material where the strength of the magnetizing force (H) no longer causes a useful increase in the flux density (B). This effect occurs at the very tip of the hysteresis loop and once it is reached, the core has entered a state of saturation. The saturation flux density (BS), and the magnetizing force required to saturate the core (HS) are shown as dashed lines.  If the current, and therefore the magnetizing force, continue to increase after the core is saturated, the inductance will begin to drop very rapidly and the component will overheat at a very fast rate, potentially damaging the wire’s insulation and causing the part to fail.  The area within the hysteresis loop represents the energy lost within the core. These losses occur in 2 forms: one being - Hysteresis loss – This is the energy lost when the magnetic/core material goes through a cycling state. Two being - Eddy current – This is caused by magnetic flux lines passing through the core material, inducing electrical currents in the material. These currents produce heat in the core. If the electrical resistance of the core is high, then the resulting currents will be low. High electrical resistivity is an important characteristic of “low loss” core material.  Core loss is a major design factor and can be controlled by selecting the appropriate core material, shape, and thickness.