CURRENT SENSOR, SENSOR ELEMENT, AND CONTROL DEVICE

A current sensor according to the present invention includes a sensor element and a detector. The sensor element includes a core member, annularly formed with a magnetic material, and having characteristics such that, corresponding to an external magnetic field that changes due to influence of a signal to be detected that passes through a detection area surrounded by the annularity, a permeability µ decreases from an vertex where the external magnetic field is 0, and such that curvature of a curve, exhibited when a change in the permeability µ is plotted in "a coordinate system defined by the external magnetic field-the permeability µ", becomes larger corresponding to absolute values of the external magnetic field. The sensor element further includes an exciting coil and a detection coil. The sensor element is configured such that, while the exciting coil is fed with an excitation signal, comprising a fundamental component, and when the signal to be detected flows, a signal, including a harmonic component, corresponding to the permeability µ of the core member at that point, being superposed on the fundamental component, is outputted from the detection coil. The detector includes a component extraction unit, a level specification unit, and an information output unit.