What is a Load Cell and The Principles Behind It?
- There are several types of force transducer principles that have been developed such as resistive, capacitive, piezoelectric, vibrating wire and magnetic. Among these, resistive transducers are the most common. These transducers are also known as strain gauges.
- The Wheatstone bridge is the circuit that can convert the change in resistance of a strain gauge into a measurable electric output.
- Elastic elements or spring material is where the strain gauge is bonded or attached. The elastic element experiences deformation which is then transferred to the strain gauge. These are classified according to the direction of load: tensile or compressive, bending and shearing.
- There are different shapes and profiles of strain gauges which are characterized by the elastic element within. Common load cell shapes are canister type, bending beam, shear beam, load pins, and so forth.
- Strain gauges consist of thin, stamp-like circuits which are prone to damage and noise. There are several constructions available depending on the application.The most airtight construction is the hermetically sealed load cell.