4. Choice of sensor gauges

The metal of the gauges must be chosen according to various criteria such as, among others:

• temperature range of use: e.g. 200°C maximum for constantan, 300°C maximum for Nichrome, etc. ;

• expansion of the test body (gauges are self-compensating, e.g. for steel, bronze, etc.);

• the variation of the gauge factor K with temperature to compensate for the variation of the modulus of elasticity E of the test body;

• the elastic limit or fatigue limit of the test body.

Gauges of the same metal form a family. The manufacturers present various families with special properties, as well as the bonding and protective products recommended for the various applications.