A position transducer is an apparatus which provides a signal which is representative of the position or the change of position of a movable element. Position transducers have many applications, such as, for example, in machine tools and in the feedback loop of a servo system for positioning aircraft flight control surfaces.
Many different kinds of position transducers are known. For example, one conventional electrical position transducer includes a ferromagnetic core and a coil, with the core being movable within the coil to vary the inductance of the coil as a function of the position of the movable element. This can be used to provide an electrical signal representative of the position of the movable element. Unfortunately, electrical position transducers are subject to various factors which adversely affect their performance, such as electromagnetic interference and R.F. interference.