| 摘要 |
<p>PURPOSE:To provide an electromagnetic induction sensor which can accurately recognize an object to be detected even via conductor by effectively bringing the object to be inspected into a magnetic field irrespective of the size of the object to be inspected. CONSTITUTION:The wiring relationship between a first sensor 5 and a second sensor 6 formed out of an exciting coil and an induction coil is so formed as to have reverse phase relationship in terms of the induction coil. If an object 1 to be inspected can not be brought into the magnetic fields formed by the sensors 5, 6, the induced electromotive voltages generated in the first and second induction coils cancel each other due to the reverse phase relationship to hold a balance. If the object 1 to be inspected is brought into one magnetic field, the balance is collapsed to generate a differential voltage. The differential voltage is used as data for recognizing the object to be detected in the object 1 to be inspected.</p> |
