RTD Fluxgate Sensors Based on Current Induced Magnetization Reversal in Twisted Glass-Coated Microwires

A new type of residence time difference (RTD) fluxgate sensor is proposed. The proposed sensor consists of a soft magnetic glass coated microwire, surrounded by a pickup coil, and an electronic system for excitation signal generation, pickup signal processing and to display the measurement result. The periodical switching of the magnetic core magnetization is performed by applying a sinusoidal electrical current directly through the magnetic material. This is the major difference from the previously proposed RTD fluxgate sensors, which use a coil to obtain the same effect. This article describes in detail the sensor operation and presents the sensor behavior for three representative categories of glass coated microwires (Fe-Si–B, Fe-Si–B-Cu–Nb, and Co-Fe–Si-B) used as sensitive elements.