| 摘要 |
PURPOSE:To reduce measuring errors, by the constitution wherein an internal magnetic field in an annular magnetic core when a vehicle is magnetized to a maximum degree is present in the linear region of a B-H curve of the magnetic core. CONSTITUTION:A geomagnetism sensor 1 comprises the following parts, an annular magnetic core 3, an exciting winding 5, which is wound around said core, two output windings 7 and 8, which are wound so as to wrap the facing side surfaces of the magnetic core 3 so that they are crossed at a right angle, and variable resistors 9 and 11, which are provided in parallel with the output windings 7 and 8. The outputs of the output windings 7 and 8 are taken out by the variable resistors 9 and 11 and inputted to operation amplifiers 24 and 25. An A/D converter 30 obtains the direction through a computer system 40. The cross sectional area and the length of the magnetic path of the annular magnetic core 3 are determined so that the internal magnetic field of the annular magnetic core 3 is present in the linear region of the B-H curve of the magnetic core 3 when a sensor 1 is placed in the maximum magnetized magnetic field of a vehicle. Thus the annular magnetic field is manufactured. |
