A load cell (or loadcell) is a transducer which converts force into a measurable electrical output. Although there are many varieties of force sensors, strain gauge load cells are the most commonly used type.
A load cell works by converting mechanical force into digital values that the user can read and record. The inner working of a load cell differs based on the load cell that you choose. There are hydraulic load cells, pneumatic load cells, and strain gauge load cells. Strain gauge load sensors are the most commonly used among the three. Strain gauge load cells contain strain gauges within them that send up voltage irregularities when under load. The degree of voltage change is covered to digital reading as weight.
A load cell measures mechanical force, mainly the weight of objects. Today, almost all electronic weighing scales use load cells for the measurement of weight. They are widely used because of the accuracy with which they can measure the weight. Load cells find their application in a variety of fields that demand accuracy and precision. There are different classes to load cells, class A, class B, class C & Class D, and with each class, there is a change in both accuracy and capacity.
There are three main ways a load cell can translate an applied force into a measurable reading.
Hydraulic load cells use a conventional piston and cylinder arrangement to convey a change in pressure by the movement of the piston and a diaphragm arrangement which produces a change in the pressure on a Bourdon tube connected with the load cells.
Pneumatic load cells use air pressure applied to one end of a diaphragm, and it escapes through the nozzle placed at the bottom of the load cell, which has a pressure gauge inside of the cell.