4.8. 1 Piezoelectric effect In Fig. 4.55 subscript i corresponds to x-axis subscript 2 to y-axis subscript 3 to z-axis uIt is evident that the piezoelectric constants are different when the directions of force application and the generated deformations are different
❑ In Fig. 4.55 • subscript 1 corresponds to x-axis • subscript 2 to y-axis • subscript 3 to z-axis. ❑It is evident that the piezoelectric constants are different when the directions of force application and the generated deformations are different. 4.8.1 Piezoelectric effect
4.8.1 Piezoelectric effect Quartz crystal is a commonly used material a quartz crystal has a shape of hexahedral structure with three mutually perpendicular axes as its crystal axes The longitudinal axis Z-Z is known as optical aXIs The axis X-X going through the edge of the hexahedron and being perpendicular to the optical axis is called electrical axIs The axis Y-y perpendicular to both the axis x X and the axis Z-Z is called mechanical axis
• Quartz crystal is a commonly used material. A quartz crystal has a shape of hexahedral structure with three mutually perpendicular axes as its crystal axes ➢ The longitudinal axis Z-Z is known as optical axis ➢The axis X-X going through the edge of the hexahedron and being perpendicular to the optical axis is called electrical axis ➢ The axis Y-Y perpendicular to both the axis XX and the axis Z-Z is called mechanical axis 4.8.1 Piezoelectric effect
4.8. 1 Piezoelectric effect applied in the electrical axis x-x is called ce The piezoelectric effect generated by the longitudinal piezoelectric effect The piezoelectric effect generated by the force applied in the mechanical axis Y-Y is called transverse piezoelectric effect Ua force applied in the optical axis z-z doesnt generate any piezoelectric effect
➢ The piezoelectric effect generated by the force applied in the electrical axis X-X is called longitudinal piezoelectric effect ➢ The piezoelectric effect generated by the force applied in the mechanical axis Y-Y is called transverse piezoelectric effect ❑A force applied in the optical axis Z-Z doesn’t generate any piezoelectric effect. 4.8.1 Piezoelectric effect
4.8. 1 Piezoelectric effect Z y (a) Fig 4.56 Quartz crystal (a)quartz crystal shape(b) the coordinate system for crystal axes(c)a cut of the crystal
4.8.1 Piezoelectric effect Fig. 4.56 Quartz crystal (a) quartz crystal shape (b) the coordinate system for crystal axes (c) a cut of the crystal
4.8.1 Piezoelectric effect There are three major piezoelectric effects, namely the longitudinal the transverse and the shear effect Q ++ +++ L== Longitudinal Traverse ear effect effect Fig. 4.57 Acting directions of piezoelectric effects
• There are three major piezoelectric effects, namely the longitudinal, the transverse and the shear effect. 4.8.1 Piezoelectric effect Fig. 4.57 Acting directions of piezoelectric effects