A capacitive transducer for sensing a home position.

摘要

A rotational shaft home position sensing transducer is provided which comprises a rotor (11) mounted on the shaft (10) having a planar surface with a first radial array of conductive elements (16) on the surface in combination with a fixedly mounted stator (12) having a planar surface parallel to the planar rotor surface and a second corresponding radial array of conductive elements (17) on the stator surface adjacent and spaced from the first array. The structure further contains a unit for applying an alternating electrical signal to the first array of elements and a unit connected to the second array of elements for sensing the capacitive effect induced in the second array by said electrical signal. The first and second arrays must be arranged so that a single home position in the relative motion between the rotor and stator will induce a single unique capacitive effect in the second plurality of elements. Particularly, the number of elements in the first and second array and their arrangement would be such that there is only a single rotational home position whereat all the elements in the first array are respectively aligned with the corresponding elements of the second array which will induce the single unique capacitive effect in this second array.