Electrical Resistance Strain Gages

An electrical resistance strain gage is a resistor used to measure strain. In its basic form, it is a wire adhered onto the surface of a component so that strains of the component are transmitted to the wire. Its operation is based on the discovery made by Lord Kelvin in 1856 that the electrical resistance of a wire increases with increasing strain and decreases with decreasing strain. By measuring the change of the resistance of the strain gage the strain is inferred. Strain gages constitute the most widely used method of measuring strain at a point.