On The Sensitivity Characteristics in Novel Automatic Wheatstone Bridge-Based Interfaces

The sensitivity characteristics of two novel fully-analog uncalibrated read-out circuits, based on a suitable modification of the classic Wheatstone bridge topology, employed for resistive sensor measurements, are here described and discussed. The proposed circuits maintain the bridge characteristics of a simple architecture and an easy estimation technique. The proved advantages of these two solutions are related to the evaluation of about 5 resistive decades variations [1000 ÷10M0] and to the reduced error confined within ±2%. Moreover, it is here demonstrated that, in the proposed interfaces, sensitivity values are higher than those of the classic Wheatstone bridge, supply-voltage independent and can be set through a proper choice of the passive element values.