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![Mechanism of Piezoelectric
The nature of the piezoelectric effect is closely related to the
occurrence of electric dipole moments in solids. The latter may
either be induced for ions on crystal lattice sites with asymmetric
charge surroundings or may directly be carried by molecular
groups. The dipole density or polarization (dimensionality
[Cm/m3] ) may easily be calculated for crystals by summing up
the dipole moments per volume of the crystallographic unit cell.
As every dipole is a vector, the dipole density P is a vector field.
Dipoles near each other tend to be aligned in regions called
Weiss domains. The domains are usually randomly oriented, but
can be aligned using the process of poling, a process by which a
strong electric field is applied across the material, usually at
elevated temperatures. Not all piezoelectric materials can be
poled.](https://image.slidesharecdn.com/piezoelectricmaterials-160622161731/85/Piezoelectric-Materials-5-320.jpg)
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Piezoelectric Materials
- 1. Presented To: RETHWANFAIZ Group Members: FARHIN, REHNUMA 14-25520-1 MIRAZ, MAGFURUL AWWAL 14-25537-1 AHMED, MD. FOYSAL 14-25539-1 CHOWDHURY, TULSI 14-25727-1 MUIN, MUHTASIM 14-25600-1 RAHMAN, MD. RABBI 14-26318-1
- 2. Content What isPiezoelectricity What is Piezoelectric materials Mechanism of Piezoelectric Motion of Piezoelectric Actuators Common Piezoelectric materials Configurations Hardware Features Applications of Piezoelectric Advantages and Disadvantages Artificial materials Signal Conditioning Conclusion
- 3. What is Piezoelectricity? Piezoelectricity is the electric charge that accumulates in certain solid materials in response to applied mechanical stress. The word Piezoelectricity means electricity resulting from pressure. The larger circles represent silicon atoms, while the smaller ones represent oxygen.
- 4. What is Piezoelectric? Piezoelectric: Piezoelectrics are materials that can create electricity when subjected to a mechanical stress. They will also work in reverse, generating a strain by the application of an electric field. The word originates from the greek word “piezein”, which means “to press”. Discovered in 1880 by Pierre Curie in quartz crystals
- 5. Mechanism of Piezoelectric The nature of the piezoelectric effect is closely related to the occurrence of electric dipole moments in solids. The latter may either be induced for ions on crystal lattice sites with asymmetric charge surroundings or may directly be carried by molecular groups. The dipole density or polarization (dimensionality [Cm/m3] ) may easily be calculated for crystals by summing up the dipole moments per volume of the crystallographic unit cell. As every dipole is a vector, the dipole density P is a vector field. Dipoles near each other tend to be aligned in regions called Weiss domains. The domains are usually randomly oriented, but can be aligned using the process of poling, a process by which a strong electric field is applied across the material, usually at elevated temperatures. Not all piezoelectric materials can be poled.
- 6. A piezoelectric diskgenerates a voltage when deformed (change in shape is greatly exaggerated)
- 7. • Shear actuators •Disk bimorph • Bimorph blenders
- 8.
- 9. • Red indicatesthe crystal • Arrows indicate the direction of applied force • The compression design features high rigidity, making it useful for implementation in high frequency pressure and force sensors
- 11. • Infineon C164CI16 bit Processor • 20 MHz clock rate • 256kB SRAM • 256kB Flash ROM • CAN 2.0B controller • 250 kbps raw data rate • RS-232 Interface • 115.2 kbps UART • DB-9 serial interface • 3 channel LISA interface • Left, Right, and microphone channels • Optional pre-amp for microphone
- 12. Applications of Piezoelectric Power generating sidewalk Gyms and workplaces Mobile keypads and keyboards
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- 16. Polycrystalline, piezoceramicsare man made materials which are forced to become piezoelectric by applying large electric field. High charge sensitivity Materials available which operate at 1000 F (540 C) Characteristics vary with temperature
- 18.
- 19. • Piezoelectricity isa revolutionary source for “GREEN ENERGY” • Flexible piezoelectric materials are attractive for power harvesting applications because of their ability to withstand large amounts of strain. • Convert the ambient vibration energy surrounding them into electrical energy. • Electrical energy can then be used to power other devices or stored for later use.
- 20.
Editor's Notes
- #11 Grey- test structure. Red- piezoelectric crystals Blue- Sensor housing The black electrode is where the charge from the crystals accumulates before it is conditioned by the yellow, micro-circuit. pressure sensors utilize a diaphragm to collect pressure, which is simply force applied over an area.
- #18 Signals from the sensors can be processed by the micro-electric circuit either internally or externally. Conditioning involves the conversion of the signal to a low impedance voltage, amplification and filtering.