How To Select a Strain Gage – Knocking on Alloys Door.

In this iLearn video, Darryl explains about strain-sensing alloys.

The principal component which determines the operating characteristics of a strain gage is the strain-sensitive alloy used in the foil grid. However, the alloy is not in every case an independently selectable parameter. This is because each Micro-Measurements strain gage series (identified by the first two, or three, letters in the alphanumeric gage designation) is designed as a complete system. That system is comprised of a particular foil and backing combination, and usually incorporates additional gage construction features (such as encapsulation, integral leadwires, or solder dots) specific to the series in question. Micro-Measurements supplies a variety of strain gage alloys as follows (with their respective letter designations):

A: Constantan in self-temperature-compensated form.
P: Annealed constantan.
D: Isoelastic.
K: Nickel-chromium alloy, a modified Karma in self-temperature-compensated form.