Electrical Circuits for Adding Strain Gauge Signals: An Investigation of Modified Wheatstone Bridge Circuits Available to Purchase

Four electrical circuits for adding strain gauge signals in various proportions are considered and their relative efficiencies and sensitivities examined. The addition is effected by slight modifications to the Wheatstone bridge circuit. In all cases expressions are given for the galvanometer current, the sensitivity and the magnitude of any extra resisters in the circuit which are necessary to effect the addition; their derivations are given in an appendix.