# Differences in strain gauge measuring grids

Discussion in 'General Electronics Discussion' started by beedees, Apr 19, 2015.

1. ### beedees

17
1
Mar 30, 2015
Hi to all!!
Maybe it would be a stupid question, but according to me it would be interesting to learn more about strain gauges and how these work! There are many types of strain gauge, different form, temperature compensation for different materials and so on.
I have to use a biaxial (two perpendicular axis) rosette with three terminals i.e. a rosette in half-bridge configuration and then instead of four terminals there are three terminals because two are the same.
The measuring grids are in constantan. Because I have to calculate the maximum initial offset of the bridge can I be sure that the two measuring grids have the same characteristics? That is tolerances and temperature coefficient of resistance? For example initial offset could increase if one grid increases its resistance and the other decreases due to temperature. Otherwise if both increase or decrease due to temperature then it isn't a problem: the initial offset (without stress) should be zero or near zero!
So how do usually strain gauge work? Can I be sure that the temperature coefficient of both measuring grids is the same?
Thanks everybody!