| 摘要 |
<p>A geophone utilizing an Alnico-9 magnet and having an improved sensitivity over Alnico-9 gcophones of prior art through the lengthening of the parasitic air gap between the upper and lower pole pieces which, results in less magnetic flux leakage. The flux concentration through the geophone coils is increased and shifted towards the ends of the magnet. The increase of sensitivity of geophone of the present invention over prior art geophonεs may exceed 3 dB. The axial length of the coil bobbin is increased, and the positions of the electrical coils are moved towards the ends of the magnet to align with the shifted magnetic flux.</p> |
