Patent ID: 7317367
Filing Date: 2008-01-08
Classification: G01D,H03K

Abstract:
1. A micro-switch comprising a movable actuator portion of electrically conductive material attached to support means so as to be movable against resilient means of the micro-switch, wherein the micro-switch further comprises at least one coil of elongate electrically conductive material mounted on the support means, such that the movable actuator portion is movable against the resilient means so as to be adjacent to the coil, and pulse inductive circuitry connected to the said at least one coil, and constructed to switch from one condition to another when the actuator portion is moved against the force of the resilient means beyond a predetermined threshold point as indicated by pulse inductive monitoring effected by the pulse inductive circuitry, wherein said inductive circuitry comprises a pulse generator that delivers a switching pulse to a pulse switch that is connected to apply a voltage to said at least one coil to provide an energizing pulse to said at least one coil such that when the energizing pulse ends. the self-inductance of said at least one coil causes the voltage across it to fall to a negative value of a magnitude well in excess of the voltage it had initially, and wherein the inductive circuitry further comprises measuring means connected across the said at least one coil to measure the inductance voltage there across at a time when the excitation energy has died away, being the inductance voltage owing to the presence of the movable actuator portion.