A Simple Linear Circuit for Angle Measurements Using a Non-Contact Potentiometer

Angular displacement is sensed by angle sensors or angle transducers. There are different types of angle sensors such as resistive, inductive, hall-effect etc., depending on their principle of operation. Amongst these, the resistive transducer, which is basically a potentiometer has many advantages such as simple operating principle, high linearity, cost-effectiveness etc. So, they are one of the highly preferred angle sensors for many applications especially automotive. In a resistive transducer, the angular displacement is converted into voltage using potentiometric principle with the help of a moving contact. But, in course of time this moving contact undergoes wear and tear and so, the accuracy of the transducer is compromised. Therefore, works have been done on non-contact, potentiometric transducers. The main difficulty associated with these non-contact potentiometers is the complexity of their signal conditioning circuits to obtain linear outputs. So, in this work, a new signal conditioning circuit with minimal complexity is proposed to produce linear outputs with the help of a differential sensing approach. The additional merit of this circuit is its single-mode operation unlike some previous works. This paper presents in detail the principle of operation of this new circuit, along with its simulation and experimental results and a discussion of some observed nonidealities.