A strain gage is a simple measuring system that determines the amount of strain, which is the displacement and deformation that results from an object under stress. It measures mechanical quantities by converting tension, force and pressure into an electrical signal. Strain gages have another spelling that is commonly known; strain gauges. This loadcell sensor type may vary in construction and measurement method.
The most popular type is foil that is adhered to the object. Other kinds include semi-conductor, bonded metallic wire and carbon resistive. When measuring the strain of an object, the temperature, material properties, the type of adhesive that bonds the gage to the object’s surface and the stability of the metal all affect the resistance. Strain gages are used to detect cracking in machinery parts, as crack propagation, as an extensometer, to measure temperature, to measure residual stress, to gage shear modulus and as a transducer.