What term describes current loss caused by a lag between an action and its effect in magnetic materials?

What term describes current loss caused by a lag between an action and its effect in magnetic materials?

• A. Hysteresis
• B. Eddy current loss
• C. Copper loss
• D. Dielectric loss

Answer: (A)

Hysteresis describes current loss caused by a lag between an action and its effect in magnetic materials. When a magnetic field is repeatedly applied and removed, the magnetic domains realign, but they don’t respond instantly. That delay means energy supplied during the cycle is partly dissipated as heat as the domains move back and forth, rather than being stored. The amount of energy lost per cycle equals the area enclosed by the B-H loop, so hysteresis loss increases with frequency and with higher peak flux. Soft magnetic materials are designed with narrow hysteresis loops to minimize this loss. This differs from eddy current loss, which comes from circulating currents induced by changing flux in a conductor and scales with frequency and material thickness; copper loss is the resistive loss in windings, and dielectric loss is energy lost in insulators due to lagged polarization, not magnetic domain realignment.

Hysteresis describes current loss caused by a lag between an action and its effect in magnetic materials. When a magnetic field is repeatedly applied and removed, the magnetic domains realign, but they don’t respond instantly. That delay means energy supplied during the cycle is partly dissipated as heat as the domains move back and forth, rather than being stored. The amount of energy lost per cycle equals the area enclosed by the B-H loop, so hysteresis loss increases with frequency and with higher peak flux. Soft magnetic materials are designed with narrow hysteresis loops to minimize this loss. This differs from eddy current loss, which comes from circulating currents induced by changing flux in a conductor and scales with frequency and material thickness; copper loss is the resistive loss in windings, and dielectric loss is energy lost in insulators due to lagged polarization, not magnetic domain realignment.