Air Core Inductor Coils  

Air Core Inductor Coils In order to achieve effective filter design, the radiation problem caused by flux leaving the core must be solved. This can be done by confining the differential mode flux to a magnetic structure (pot core), or by providing a path of high permeability for the differential mode flux (E core). If the common - mode choke has a kettle-shaped iron core structure, then two winding shafts are required. Two sets of coils in a kettle-shaped iron core pane and their resulting flux paths. The differential mode flux path with the same structure is also shown. There is also a common mode choke, which is easier to wind than a toric-core coil but emits more radiation than a kettle-core coil. The common mode flux of an E-core coil connects both sets of coils on the outer lead. In order to obtain high permeability, there should be no air gap in the external lead. The differential mode flux, on the other hand, connects the outer lead to the center lead. The permeability in…