| 摘要 |
<p>In a magnetic detection element using a magnetic impedance element utilizing the magnetic impedance effect, the condition to obtain a linear output and the magnetic field size capable of obtaining a linear output depend on the characteristic of the magnetic impedance element. Accordingly, in order to increase the detection sensitivity within a limited operation range, a method of applying the AC bias magnetic field to the magnetic impedance element is used. However, when considering application to an overload current safety device such as a thermal relay, there is a defect that the current detection range is small and cannot be used in practice. To cope with this, as the bias magnetic field applied to the magnetic impedance element, firstly, a positive-negative equivalent bias magnetic field is applied and according to the obtained output polarity, the magnetic polarity of the magnetic field to be measured is judged, so as to generate a variable type bias magnetic field of a different magnetic field intensity with the magnetic field polarity effective for the judged external magnetic field polarity.</p> |
