摘要 |
A non-contacting capacitive position transducer comprises a stator substrate carrying two electrically conducting inverted wedge regions 14,16 whose width varies inversely in a sensing direction. A moveable pick-off 20 is capacitively coupled to both wedges. The wedges 14,16 are driven with respective distinguishable time varying periodic waveforms, e.g. a sine wave and a cosine wave, and the pick-off voltage at 20 processed to determine the position of the pick-off in the sensing direction. Various configurations of transducer are described, including those of linear, cylindrical and disc form. The pick-off voltage is preferably transferred from the pick-off 20 back to the stator by capacitively coupling the pick-off to a suitably screened pick-off track 36 on the stator. |