Load Cell Essay

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LOAD CELL Definition of the “load cell’’ Load cell is a Sensor which converts non electrical signal i.e. forces (mass, torque) into electrical signals. Load cells may also be termed as “load transducers.” Or A load cell is a transducer which created electrical signals whose magnitude varies proportionally to the applied force. Load cells are of different types which include hydraulic, pneumatic and strain gauges load cells. Or A load cell may also be described as a “weight measuring device’’ which is necessary for electronic scales of displaying weight in digits. Load cells can be classified according …show more content…

The deformation of a strain gauge measured (strain) as a resistance change; the measure of a strain is hence an applied force. In a load cell there is a Wheatstone bridge configuration consisting of 4 strain gauges. Load cells are also available in Quarter Bridge configuration i.e. consisting of a single strain gauge or half bridge configuration of 2 strain gauges. The output of a load cell is typically in the range of milli-volts hence requires amplification through an instrumentational amplifier. When a mechanical structure is subjected to some force, it undergoes deformation .stress describes the intensity of force on a structure as force per unit area Stress=F/A Strain describes the deformation as the fractional change in length Strain=∆L/L Young’s modulus describes the stiffness of the structure as the ratio of stress to strain. if the structure is very stiff a large stress is required to produce a given strain and young’s modulus is large. One of the simplest resistive strain gauge is a rubber tube filled with mercury, as the rubber tube is stretched, its length L increases and its cross-sectional area A decreases. The electrical resistance is given …show more content…

The conversion in strain gauge type load cells is indirect and happens in two stages. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge measures the deformation (strain) as an electrical signal, because the strain changes the effective electrical resistance of the wire. The strain gauge is bonded to a structure so that the percent change in length of the structure and the strain gauge is identical. A load cell usually consists of four strain gauges in a Wheatstone bridge configuration. Strain gauges load cell converted the applied load acting on it into electrical signals. The gauges deforms when are bonded on a structural or beam member on weight application. In many cases for maximum sensitivity and for temperature compensation four strain gauges are used. Usually Two gauges are in tension, and other two in compression, which are wired through compensation adjustment .On application of force (weight), the strain deforms to the electrical resistance of the gauge proportional to the load. LOAD

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