Displacement or strain gauge - uses deformable body with impedance varying as function of measured physical parameter

摘要

The sensor uses a membrane subjected to a given stress to determine a related physical parameter. The sensor can be connected directly to a display without requiring an electronic amplification and can be powered by an AC or a DC supply. The operation is based on the variation of impedance of a body placed under stress, this variation being a function of the measured parameter. The sensor can be formed by associating an elastomer with a conductive material, or a metal with its oxide, or glass with carbon etc. Alternatively, the sensor can be formed by associating any insulator with a conductive body, using a fibre, liq. plastic powder or even a metal. Under stress, the conductive elements draw closer together and the resistance of the assembly tends to diminish or vice-versa.