In each converter, which converts the element is based on certain physical principle, which is associated with the electrical characteristics of the device so that a change in the quantity being measured >>>
measurand grows into the change of electrostatic charge or tension, arising up in some materials at their mechanical tension. Tension usually appears under the action of forces of compression, tension or bend, which are a measurand and affect pickoff either directly or by means of some mechanical connection.
To perceive the change of charge or tension, to piezoelectric material connect two metallic plates, which form the plates of condenser the capacity of which is determined in a kind actually
C = Q/V
where Q is a charge; V is tension (voltage).
As piezoelectric material, applied in the construction of such transducer, used: 1) natural crystals, such, as a quartz or rochele salt; 2) synthetic crystals, for example sulfate of lithium; 3) the polarized ferromagnetic ceramics, for example титанат of barium.