ABSTRACT
This chapter reviews physical principles that can be used for pressure transducers which include thermal, electrostatic, electrokinetic, gas discharge, and mechanical deformation effects of pressures. The principles used for biomedical pressure transducers are summarized, including piezoelectric, piezoresistive, semiconductor junction, and mechanical deformation. The mechanical deformation can be visible in the classical sense or in microdeformation, as in the crystal structure. Biomedical pressure transducers operate on the following major principles: piezoelectric effect, piezoresistive transducer and Silicon strain gauges. Most of the mechanically deformed biomedical pressure transducers are used to convert the displacement into electrical signals that can be processed later. The common principles are summarized as follows: capacitive, inductive, resistive, Optical, vibrational, volumetric and fluid column manometer. Various methods of detecting the height of the fluid column by optical, inductive, or other means can be used to translate the column height and pressure into electrical signals. The method of supplying power to the indwelling pressure transducer is also a problem.
