Digital Differential Capacitive Angle Transducer

A high accuracy, easy to fabricate, capacitive angle transducer that provides a digital output linearly proportional to the angle being sensed in the range 0deg to 360deg is presented. The variations in the sensor capacitances are converted to digital employing dual slope digital conversion principle. High accuracy is easily obtained since the output is dependent only on a dc reference voltage and a high frequency clock. The signal conditioning circuitry is configured such that the effect due to stray capacitances on the output is completely eliminated. A prototype developed and tested validates the practicality of the proposed method.