An electromechanical generator for converting mechanical vibrational energy into electrical energy, the electromechanical generator comprising a housing, an electrically conductive coil assembly fixedly mounted in the housing, the coil assembly having radially inner and outer sides, and upper and lower edges, thereof, a mount for the coil assembly extending inwardly of the radially inner side for fixing the coil assembly in a fixed position in the housing, a magnetic core assembly movably mounted in the housing for linear vibrational motion along an axis, and a biasing device mounted between the housing and the magnetic core assembly to bias the magnetic core assembly in opposed directions along the axis towards a central position, wherein the magnetic core assembly encloses the electrically conductive coil assembly on the radially outer side and on the upper and lower edges, and on a part of the radially inner side, the magnetic core assembly having a gap on a radially inner portion thereof through which the mount extends, and the radially inner portion including two opposed magnets spaced along the axis.