What is the principle of operation of a load cell?

A strain gauge load cell consists of a metal body (stainless steel or aluminium) to which strain gauges are applied. The strain gauges are constituted by a grid of thin metal wire (constantan) applied to a support of insulating material and glued into specific areas of the load cell. The strain gauges follow the deformations of the surface of the load cell to which they are bonded, lengthening and shortening along with it; these dimensional changes cause a variation in electrical resistance, which through the "Wheatstone Bridge" connection, is converted into a proportional electric signal normally expressed in mV (thousandths of a volt).

Read more: What a load cell is and how it works.