Least squares best fit line method for the evaluation of measurement uncertainty with electromechanical transducers (EMT) with Electrical Outputs (EO)

In the electromechanical type indirect pressure indicating devices (IPIDs), the applied pressure is indirectly computed by some relationship between applied pressure and an analog / digital electrical signal in terms of voltage, current or frequency measured by a sensing element of such devices. If the output of an EMT in terms of any electrical quantity i.e. voltage, current or frequency, is related / dependent upon input quantity i.e. pressure then this relationship can be defined by a curve that has been fitted to experimental data by method of least square. The calculation of the calibration results and the associated uncertainties is a complex matter involving many influencing quantities. The present paper describes a method for calibration and evaluating uncertainty in pressure measurement using such EMTs with EOs through statistical analysis of errors.