Patent ID: 7046018
Filing Date: 2006-05-16
Classification: G01D

Abstract:
1. A position sensor comprising: a coil; one selected from: an electric conductor and a magnetic member, each having an area overlapping at least a part of the coil, with the coil and the selected electric conductor or magnetic member being arranged together so that a size of the overlapping area varies as a position of an object whose position is being determined changes; a resistor connected in series with and constituting a series circuit together with the coil, such that the resistor has a resistance value greater than zero so that a period of oscillation of the circuit is minimized; a capacitor arranged to be alternatively charged and discharged through the series circuit of the coil and the resistor; and an inverse output comparator for receiving a charging voltage of the capacitor as an input; for conducting charging of the capacitor when an output is at a high level, and for conducting discharging of the capacitor when the output is at a low level; such that a displacement of the object being examined is detected as a change in period of a continuous oscillation motion; wherein a resistance of the coil a resistance of the resistor, a capacitance of the capacitor, and a threshold voltage of the comparator are determined so a change in period is minimum when at least one of the resistance of the coil, the resistance of the resistor, the capacitance of the capacitor, and the threshold voltage of the comparator is varied, and when a temperature is at a predetermined level.