A Simple Digitization Scheme for Resistive Sensors and its Adaptation for Remote Measurements

A simple digitization for resistive sensors is proposed in this article. The scheme uses readily available electronic components and provides a digitized indication of resistance. The non-ideal parameters such as bias current and offset voltage of Op-amps and drift of power supply, do not affect the output measurements. Later, an improved version of this digitizer is proposed to measure remotely-located sensors, with the help of the three-wire measurement technique. This enhanced circuit also provides added advantages like immune to drifts of the capacitor and the mismatch between the high and low-level voltages of the components used in the scheme. The operation and analysis of the digitization schemes are elaborated in this article. The performance of the proposed schemes is also verified using simulation studies. The maximum nonlinearity is merely 0.02 %.