As resistance of explorer is determined by correlation
R = rL/S
where r is specific resistance of material; L - length S is an area of cross-sectional, that resistance can change at any oscillation of measurand which influences on one or a few arguments included in this expression.
The brought dependence over is used in strain gauge - transducers which convert a change made effort into the change of resistance (fig. 1). As a rule, such transducers is used together with the bridge of Uytstona, when one, two or even all four shoulders present by itself strain gauge, and output tension changes in reply to variations of measureable effort.
Metallic transforming elements are used in strain gauge, at the appendix of the mechanical loading which a change of their length and area of cross-sectional is to, that leads, in turn to the change of resistance. Some materials of strain gauge, for example semiconductor, show a piezoelectric effect at which loading attached to material causes the large change of his specific resistance. Strain gauge of such type possess a greater sensitiveness on two orders, what before considered.
In general case any parameter which reproduces motion or force can be used for creation of strain gauge transducers.
Physical basis of the transformation of the measured parameters
In each converter, which converts the element is based on certain physical principle, which is associated with the electrical characteristics of the device so that a change in the quantity being measured >>>