Digital Capacitive and Strain Gage Load Cell Technologies Compared
Capacitive and strain gage load cells both relies on an elastic element which is deformed by the load to be measured.
The material used for the elastic element is normally aluminum for low cost load cells and stainless steel for load cells used in corrosive industrial applications.
A capacitive respectively a strain gage sensor measures the deformation of the elastic element and the output of the sensor is converted by an electronic circuit to a signal which represents the load.
A capacitive sensor is a conductor which, placed at a small distance from the elastic element, measures the deformation without any contact with the elastic element while a strain gage is an insulated resistance foil which is bonded directly to the elastic element and which is consequently exposed directly to the shocks and overloads, frequently met in industrial applications.
Furthermore a capacitive sensor is very sensitive with a change of capacitance of 10% while the foil strain gage normally only has a change of resistance of 0.1%.
Cabling and sealing
The high change of capacitance lends itself to provide a digital output signal which in the Eilersen capacitive load cells is a high speed signal, representing the load directly in g, kg or Newton.
With reference to the above-mentioned merits of the Eilersen capacitive and the strain gage load cells the following can be concluded:
The Eilersen shockproof load cells hammer test: