Force sensors based on strain gauges are mostly implemented in form of a bending beam , whose top and bottom side has one or more stain gauges each. If a force F is exerted on the beam end, then the strain gauges on the top side are expanded and those on the bottom side are compressed. The resistance of the top side strain gauges increases and the resistance of those on the bottom side decreases. This resistance variation is then a measure of the acting force and can be evaluated, for example, with the aid of a bridge circuit.