High sensitivity variable inductance - uses winding around toroidal core whose polarisation is changed by magnet mounted on flux concentrating element

摘要

A variable inductance is wound in a straight former on a toroidal core. The inductance is changed by altering the core polarisation using a magnet or electromagnet placed around the core. The core is formed in two U-shaped halves from a combination of ferrite and high permeability metal. The wire is uniformly wound radially w.r.t. the principal axis of the core. Field closing elements surround the core and are made of ferrite or high permeability material. The device extends in the direction of the external magnetic flux by a volume of material having a permeability adapted to concentrate the flux. A magnetic is slidably mounted on the flux concentrating element to provide polarization and an initial frequency. The conductor is used in digital oscillation or phase locked loops.