| 摘要 |
PURPOSE:To enable detection of the location of an object containing magnetic material even under unfavorable condition by detecting the existence of a magnetic body causing turbulence of geomagnetism according to an electric signal induced in a coil based on the turbulence of the geomagnetism. CONSTITUTION:When the magnetic body exists around the coil 1, there appears turbulence in the distribution of magnetic flux of geomagnetism. The coil 1 makes rotation at a fixed speed in the gradient of magnetic field and in the coil 1 is induced an electric signal corresponding to the gradient of magnetic field and the rotational number thereof. This electric signal is led to a receiver 10 through slip rings 5 and brushes 7, the component of frequency corresponding to the rotational speed of a rotary arm 4 is extracted therefrom by a band-pass filter 11, and a signal obtained from extraction is led to an indicator 14 through the intermediary of an amplifier 12 and a filter 13. |
