Quarter-Bridge Strain Gage - Shunt Calibration

* Where the measurement equipment cannot be calibrated with sufficient accuracy by the direct effect of the measured quantity on the active strain gage R4, a shunt resistance (Rp) is used to intorduce an known unbalance to the bridge circuit [1]. * R4 is an active strain gage measuring the tensile strain (+ε) and ranging from 119.5Ω to 120.5Ω in i.e. +/- 2000 um/m for a gage factor k = 2. * R3 is a passive resistor known as dummy [2]. * Requires half-bridge completion resistors (R1, R2) to complete the Wheatstone bridge. References: [1] Hoffmann, K. An Introduction to Measurements Using Strain Gages. Hottinger Baldwin Messtechnik GmbH, Darmstadt. 1989. [2] http://www.ni.com/white-paper/3642/en/