Linearity and Sensitivity Error in the Use of Single Strain Gauges with Voltage-Fed and Current-Fed Circuits
An important part of experimental stress analysis is the measurement of strain with single strain gauges. Here, the type of circuitry employed influences the linearity and sensitivity of the measurements.
This article describes the basic principles of strain measurement by means of strain gauges, from the strain itself via the variation in resistance to the eventual electrical signal, and compares the magnitude of error of the voltage-fed bridge circuit and the current-fed circuit.
The conclusion reached is that, for single strain gauges, voltage-fed bridge circuits give better linearity by several powers of ten and, when there is initial detuning, a similarly more stable sensitivity than current-fed circuits.