Comparative evaluation of the two current source supplied strain gauge bridge

Abstract

Metrological properties of a two-current-source bridge circuit were tested with the use of the method of measuring resistance increments of strain gauges. An unconventional system was investigated in comparison with the commonly used Wheatstone's half-bridge, quarter-bridge and Anderson's loop. Input-output characteristics of the systems tested with a current supply were examined experimentally. Error values of offset and gain of the characteristics in relation to the characteristics of reference were taken as the criterion of comparison. Moreover, standard uncertainties of y-intercept and slope coefficients (of the straight lines) were analysed. The coefficients with their uncertainties are presented in tables. Errors for three tested systems with two metal strain gauges or with one semiconductor are presented on graphs. Additionally, the errors change, resulted from the spread of initial resistances as the quantity influencing the uncertainties of offset and gain coefficients, was defined for the bridge circuits.