Tunable magnetic core structure

A tunable magnetic assembly includes a bobbin, an outer core, and an inner core. The bobbin has a first and second flanges. The bobbin has a passageway extending between the first and second flange. The passageway has a spiral track defined in a passageway surface. The outer core is positioned around the first and second flanges. The outer core includes an opening positioned near the first flange. The inner core is positioned in the opening and in the cylindrical passageway. The inner core includes at least one protrusion extending from an outer surface and configured to engage the spiral track. A gap distance is defined between the inner core and a portion of the outer core near the second flange. The gap distance is adjustable by moving the protrusion within the spiral track. Adjusting the gap distance modifies the inductance.