Resistance strain gauge pressure transducer

Piezo-resistive pressure transducers offer a number of advantages [82]. The transducer is quite robust because of the relatively thick diaphragm. There is no liquid fill inside the transducer as a result, there is no concern about leakage of mercury. The natural frequency of piezo-resistive transducers is about three orders of magnitude better than strain gauge type transducers. As a result, the dynamic response of piezo-resistive transducers is very good compared to that of strain gauge transducers. 

Transducers Many measurements cannot be used for control until they are converted to physical quantities (such as electric voltage or current, or a pneumatic signal, i.e., compressed air or liquid) which can be transmitted easily. Transducers are used for that purpose. For example, strain gauges are metallic conductors whose electric resistance changes when they are subjected to mechanical strain. Thus they can be used to convert a pressure signal to an electric one. 

Force/pressure transducers The simplest force measures use load cells based on an LVDT, which displaces by a small amount as a force is applied. Strain gauges can measure the (small) deformation of thin film attached to a surface by measuring the resistance of an attached conducting element. 

Strain gauge or piezo-resistive pressure transducers can be bought as versions for absolute and gauge pressure. One disadvantage is the high temperature drift of the zero signal which constrains the measurement range to two pressure decades. 

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