Wheatstone Bridge Strain Gauge

Wheatstone bridge strain gauge circuits are used extensively inside the transducer to convert a mechanical strain into an electrical output signal.

The basic circuit consists of four resistive elements which are connected together into a diamond shaped configuration. Typically all 4 resistive elements are active strain gauges to maximise sensitivity of the transducer but in some cases 2 fixed resistors are used with 2 strain gauges instead.

A Wheatstone bridge strain gauge circuit is created by mounting a pair of strain gauges on a material that will be stressed, so that when a force is applied, they will stretch along their width. Another pair of identical strain gauges are mounted in a direction at 90° to the other pair, where the applied force will stretch them along their length.

The simplest way to achieve the wheatstone bridge configuration is to mount all four strain gauges onto the measurement surface in a radial configuration separated by 90 degrees, with all strain gauges pointing in the same direction.