| 摘要 |
An apparatus for detecting damped wave disturbances includes a hollow tubular housing of electrically nonconductive material with a pair of electrodes extending through apertures in each end of the housing such that the inner ends of the electrodes are spaced apart a predetermined distance within the housing. Ferro-magnetic electrically conductive particles are disposed loosely within the housing of sufficient quantity to form an electrical bridge between the electrodes when the particles are influenced by a magnetic field. A pair of annular collars of electrically conductive material are fastened to the housing and spaced coaxially apart, with one collar electrically connected to an antenna and the second collar electrically connected to ground. The particles within the housing have a very low electrical resistance when influenced by a magnetic field, so as to form an electrically conductive bridge. The particles also have a very high electrical resistance when not influenced by a magnetic field. The outer ends of the electrodes are electrically connected to an electrical circuit which preferably will operate an active device in response to the detection of the damped wave disturbance.
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