Patent ID: 7276897

Claim:
An apparatus for determining a part position of a movable part, comprising: a transmitter coil, the transmitter coil generating electromagnetic radiation when the transmitter coil is excited by an a source of electrical energy; a receiver coil disposed in proximity to the transmitter coil, the receiver coil generating a receiver signal when the transmitter coil is excited due to an inductive coupling between the receiver coil and the transmitter coil; a reference coil, the reference coil generating a reference signal when the transmitter coil is excited due to a second inductive coupling between the transmitter coil and the reference coil, the second inductive coupling being substantially independent of the coupler element position; and a coupler element, the coupler element being moveable and having a coupler element position correlated with the part position, the coupler element modifying the inductive coupling between the transmitter coil and the receiver coil so that the receiver signal is correlated with the part position, wherein the receiver coil includes a first loop configuration and a second loop configuration, the first loop configuration and second loop configuration having opposite winding directions.