Patent ID: 6317021
Filing Date: 2001-11-13
Classification: H01F

Abstract:
A variable inductor comprising;a core formed of a saturable magnetic material, said core having three legs, including a center leg and two outer legs;a control winding on the center leg and windings on each of the outer legs connected in parallel and in such a way that the magnetic flux arising from currents through the windings on the outer legs is cancelled in the center leg;wherein a current through the control winding causes a changed inductance across the windings on the outer legs by changing the saturation level of the outer legs, wherein the inductance of the control winding is substantially constant with a change in current in the control winding;the magnetic cross-section of the center leg, relative to the magnetic cross-sections of the outer legs, being such that the outer legs and the center leg have substantially equal saturation levels.