Unbalanced-bridge Computational Techniques and Accuracy for Automated Multichannel Strain-measuring Systems

While much of the current literature and practice is concerned with balance-bridge strain measurements, this paper outlines a straightforward method for measuring strain using unbalanced-bridge techniques. Exploiting the performance and stability available in today's digital voltmeters and low-cost computers, it will be shown that the use of unbalanced bridges is well suited to automated strain measurements. The paper also presents a method for assessing the accuracy of a strain-measurement system by using the specifications of the individual components. Additionally, a comparison of accuracy for balanced and unbalanced conditions is included in this assessment.