An apparatus for measuring the relative displacement between a first shaft and a second shaft, comprising: a first rotor assembly being coupled to the first shaft and being centered on an axis; at least one magnet having a magnetic field and being disposed on the first rotor assembly; a second rotor assembly being coupled to the second shaft, the first and second rotor assemblies (24, 26) being coaxial, the second rotor assembly having a first stator plate and a second stator plate, the first and second stator plates (66, 68) having a circular base section (66C, 68C) and a plurality of teeth (66D, 68D) extending from the base section (66C, 68C) in a direction radial of the axis; a flux collector arrangement having a first collector and a second collector, the first and second collectors (110A, 110B) each surrounding at least a portion of an outer rim (66G, 68G) of the first and second stator plates (66, 68), respectively, and each having a side section and a base section defining a curved first surface, the curved first surface of the first and second collectors (110A, 110B) being spaced from the outer rim (66G, 68G) of the base section (66C,68C) of the first and second stator plates (66, 68), respectively, the first and second collectors (110A, 110B) having a second surface (114A, 114B), the second surface of the first collector and the second surface of the second collector being parallel and forming a gap, wherein each of the second surfaces is formed by a tooth extension extending outward in a direction away from the respective base section; and a sensing device disposed within the gap for sensing a magnetic flux of the magnetic field, characterized in that the base section, the tooth extension and the side section of each of the first and second collectors (110A, 110B) all cover the same portion (in degrees) of the respective stator plate (66, 68). a first rotor assembly being coupled to the first shaft and being centered on an axis; at least one magnet having a magnetic field and being disposed on the first rotor assembly; a second rotor assembly being coupled to the second shaft, the first and second rotor assemblies (24, 26) being coaxial, the second rotor assembly having a first stator plate and a second stator plate, the first and second stator plates (66, 68) having a circular base section (66C, 68C) and a plurality of teeth (66D, 68D) extending from the base section (66C, 68C) in a direction radial of the axis; a flux collector arrangement having a first collector and a second collector, the first and second collectors (110A, 110B) each surrounding at least a portion of an outer rim (66G, 68G) of the first and second stator plates (66, 68), respectively, and each having a side section and a base section defining a curved first surface, the curved first surface of the first and second collectors (110A, 110B) being spaced from the outer rim (66G, 68G) of the base section (66C,68C) of the first and second stator plates (66, 68), respectively, the first and second collectors (110A, 110B) having a second surface (114A, 114B), the second surface of the first collector and the second surface of the second collector being parallel and forming a gap, wherein each of the second surfaces is formed by a tooth extension extending outward in a direction away from the respective base section; and a sensing device disposed within the gap for sensing a magnetic flux of the magnetic field, characterized in that the base section, the tooth extension and the side section of each of the first and second collectors (110A, 110B) all cover the same portion (in degrees) of the respective stator plate (66, 68).