Abstract: A geophone is disclosed that has a cylindrical housing closed at one end by a bottom and at the other end by a top. A magnet assembly and a coil-mass are located in the housing. Springs support the coil-mass for axial movement relative to the magnet assembly along the longitudinal axis of the housing. A pair of coil terminals are mounted in the upper end of the coil-mass adjacent the top of the housing. A pair of eyelets extend through the top of the housing and outside geophone terminals are attached to and extend through the eyelets into the housing. A pair of pigtails connect the geophone terminals to the coil terminals.

Abstract: A seismic detector assembly is disclosed that includes a housing and a seismic detector or geophone located in the housing. The geophone has a pair of external terminals that are positioned asymmetrical to the longitudinal axis of the geophone. A printed circuit board having conductive strips for connecting the terminals to leader cables is located in the housing above the geophone. The printed circuit board has a pair of asymmetrical openings through which the asymmetrical terminals can extend only when the printed circuit board is oriented in one position relative to the geophone. Marks on the printed circuit board indicate which conductive strip should be connected to which terminal and the proper orientation of the printed circuit board relative to the truck that receives the output of the geophone.