| 摘要 |
PURPOSE:To keep the direction of a magnetic field constant all the time and to increase the intensity of the magnetic field applied to the magnetic body, by providing a unitary body of an electromagnet or a permanent magnet and at least one or more sensors. CONSTITUTION:A magnetic sensor 2 is provided at the center of the permanent magnet 1 whose static magnetic field (direction of z) becomes zero. When the magnetic body is not located in the vicinity of the sensor, the output of the magnetic sensor 2 is zero. When the magnetic body 4 to be detected approaches the detecting device 3, the magnetic body 4 is magnetized by the magnetic field of the permanent magnet 1, and the magnetic field distribution, which is formed only by the permanent magnet 1, is disturbed. Therefore, the magnetic field at the position of the magnetic sensor 2 is no longer zero. Then an output is generated from the magnetic sensor 2. The output of the magnetic sensor 2 is amplified by an amplifier 5 and sent to a meter 6. Thus the magnetic body can be detected. |
