Abstract: An electrical switch sensitive to an externally applied inertial and gravitational force, having an enclosure with a closed space; a conductive fluid filing a first portion of the space and a non-conductive medium filling a second portion of the space, the conductive fluid and the non-conductive medium having differing densities; at least two electrodes in communication with the space; an electrical circuit coupled the contacts and having electrical connections for connection with a power source and a load, having a semiconductor switching device, which is responsive to a current through the contacts, a current through the contacts causing the semiconductor switching device to change in conductivity. An externally applied force, e.g., gravity or inertial force, causes the conductive fluid to move within the enclosure with respect to the contacts, altering a current through the contacts, and thereby changing a conducting state of the semiconductor switching device.