Resistance-based Calibration of a Double Bias Elimination Resistance Measurement Circuit

The elimination of measurement bias contributes to the final accuracy of an instrument. Other techniques that contribute to final accuracy include ratiometric measurement. A circuit including both of these techniques (and... [ view full abstract ]

The elimination of measurement bias contributes to the final accuracy of an instrument. Other techniques that contribute to final accuracy include ratiometric measurement. A circuit including both of these techniques (and others) has previously been described, in which the analogue-to-digital conversion of the voltage across the device under test eliminates bias, but the conversion of the voltage across the ratiometric reference resistor does not. A double bias elimination circuit has also been previously described, which adds elimination of bias for the reference resistor. This circuit would be most useful in specialized investigations of, for example, the behaviour of materials over narrow temperature ranges. Here, we describe the circuit’s operation in detail, and propose a cost-effective calibration method to maximize the benefits of the design, based on the high precision and stability available at relatively low cost from purpose-made resistors.