Soft magnetic inductors are electronic components, mainly composed of circular magnetic core, iron powder, ferrite, wire around it, or other materials to make a speaker inductor. Longitudinal field coils are used in a wide range of applications such as high frequency coils and transformers. Soft magnetic inductors can have higher Q factors and higher inductance configurations than the same solenoid coils. This is largely due to the small number of turns needed to provide a closed core magnetic path. At a high permeability this flux is confined to the core, and the energy dissipated by confinement is reduced and can be absorbed into nearby objects, so the toroid provides some of the core. The magnetic field flux direction is geometrically in the center of the threaded ring, while the soft magnetic flux direction is parallel to the core of the ring.
Introduction to Toroidal Coil Inductors