Figure 1.
The schematical diagram of: (a) parallel fluxgate magnetic sensor and (b) orthogonal fluxgate magnetic sensor. The word “parallel” and “orthogonal” in the name mean the orientation between the excitation magnetic field and the probed magnetic field. In (a), the excitation magnetic field Hex is parallel to the probed magnetic field Hdc. In (b), the excitation current is along the axial direction. So, the excitation magnetic field is around the circle and orthogonal to the probed field Hdc. Only the orthogonal fluxgate sensor needs the DC exciting current which should be sufficiently larger than the AC exciting current.