Attachment of strain gauges in a ring spring element may
cause two main problems: the generation of an offset by the
Wheatstone bridge imbalance due to its internal and external
curvature and the angular misalignment. The error due to bad
angular positioning can be avoided, but the imbalance due to
curvature cannot. Because of this, all the developed prototypes
presented an initial imbalance that had to be corrected by an
auxiliary parallel trimming resistance.