Views:27 Author:Site Editor Publish Time: 2020-04-15 Origin:Site
Load Cell Operating Principle
Strain gauge load cells convert the load acting on them into electrical signals. The gauges themselves are bonded onto a beam or structural member that deforms when force is applied. In most cases, four strain gauges are used to obtain maximum sensitivity and temperature compensation. Two of the gauges are usually in tension, and two in compression, and are wired with compensation adjustments. When a load is applied, the strain changes the electrical resistance of the gauges in proportion to the load. Other load cells are becoming less popular as strain gauge versions continue to increase their accuracy whilst reducing unit costs.
The early load cell designs simply use a strain gauge to measure the direct stress, which is introduced into a metal element when it is subjected to a tensile or compressive force. A bending beam type design uses strain gauges to monitor the stress in the sensing element when subjected to a bending force. More recently, the measurement of shear stress has been adopted as a more efficient method of load determination, as this method is less dependent on the direction in which the force is applied to the load cell.
Other types of load cell used include hydraulic (or hydrostatic), pneumatic, piezo-electric and vibrating wire load cells. Read more about load cells on Wikipedia.