Quick-response accelerometer

An acceleration sensor comprises a tube (14) formed of an electrically-conductive, nonmagnetic material; an annular magnetically-permeable element (18), such as a iron washer, encircling a longitudinal portion of the tube (14); a magnetic sensing mass (32) in the tube which magnetically interacts with the washer (18) so as to be magnetically biased towards a first or "rest" position in the tube (14) characterized in that a longitudinal portion of the sensing mass (32) is situated within the portion of the tube (14) encircled by the washer (18), the sensing mass (32) being displaced from its rest position in the tube (14) towards a second position therein in response to an accelerating force exceeding the magnetic bias thereon; and a switch (28) operated by the sensing mass (32) when the sensing mass is displaced to its second position in the tube (14). The instant accelerometer features a low threshold magnetic bias of the sensing mass to provide a quickened sensing mass response to acceleration inputs of short duration; and a magnetic bias which increases in a substantially linear manner with increasing sensing mass displacement from its rest position towards its second position within the tube (14).