1. Sensing Element
The component that directly detects the measurand (mass) and outputs another quantity with a defined relationship to that measurand. Examples include the elastic body of a resistance strain-gauge load cell, which converts the mass of the object being weighed into deformation, and the elastic body of a capacitive load cell, which converts the mass into displacement.
2. Transducing Element
Also known as the sensor element, this component converts the output of the sensing element into a signal that is convenient to measure. Examples include the resistance strain gauge (or strain foil) in a resistance strain-gauge load cell, which converts the elastic body's deformation into a change in electrical resistance, and the capacitor in a capacitive load cell, which converts the elastic body's displacement into a change in capacitance. Sometimes, a single component performs the functions of both the sensing element and the transducing element; for instance, the piezoelectric material in a piezoelectric load cell outputs an electrical quantity simultaneously with its deformation under an external load.
3. Measuring Element
This component converts the output of the transducing element into an electrical signal, facilitating further transmission, processing, display, recording, or control. Examples include the Wheatstone bridge circuit in a resistance strain-gauge load cell and the charge preamplifier in a piezoelectric load cell.
4. Auxiliary Power Supply
Provides energy for the sensor's electrical signal output. Generally, load cells require an external power supply to operate; therefore, power supply requirements must be specified for the product, although the power supply itself is not considered a component of the load cell. Some sensors-such as magnetoelectric velocity sensors-output sufficient energy to operate without an auxiliary power supply; thus, not all sensors require one.