Application of piezoelectric ceramics II

2. Application in electro-acoustic and other equipment

This application is a kind of transducer that converts electric energy into sound energy or converts sound energy into electric energy through piezoelectric effect. There are piezoelectric ceramic speakers, receivers, and buzzers.

(1) Piezoelectric ceramic receiver

The receiver is the receiver, usually electromagnetic or electric, but the piezoelectric ceramic receiver has the characteristics of light weight, no fear of electromagnetic interference, and miniaturization.

(2) Piezoelectric ceramic buzzer

Piezoelectric ceramic buzzer is an electroacoustic device made of piezoelectric ceramic sound element (commonly known as buzzer). Compared with electromagnetic buzzer, it has the following advantages

①No contact, high reliability, long life, no radio noise;

②Clear tone, strong penetrating ability in noise;

③Change the circuit, which can emit various tones;

④The power consumption is small, the working current is very small, only 1/10~1/2 of the electromagnetic buzzer;

⑤Small size, light weight, thin thickness, suitable for integration needs.

Piezoelectric ceramic buzzers are used in many factories, such as fire alarms, smoke and gas alarms, car speed alarms, anti-theft alarms, mine gas alarms; electronic watches, electronic doorbells, electronic calculators, instruments, etc. time and audio transmission instructions: electronic toys, music cards and remote callers use piezoelectric buzzers extensively.

Piezoelectric ceramic buzzer generating elements generally use diaphragms, with an external dimension of 10~50mm in diameter and a total thickness of 0.4~0.5mm. When an alternating voltage is applied to the piezoelectric ceramic generating element, the sound generating element generates flexural vibration and emits sound.

Piezo Ceramic Buzzer

 

3. Application in measuring instruments

Piezoelectric ceramics are used to make various sensors for measuring and sensing various dynamic or static forces, accelerations, shocks and vibrations and their changes. It has been used in various detection instruments and control systems, and has become a key component of these instruments and control systems. Such components include piezoelectric gyroscopes, piezoelectric accelerometers, piezoelectric ceramic pressure gauges, piezoelectric flow meters, and frost sensors. Surface roughness measuring instrument, piezoelectric electronic scale, etc.

If mass is added to the piezoelectric body, an accelerometer can be made. That is to say, a force proportional to the product of mass and acceleration is added to the piezoelectric body, and its output voltage is proportional to acceleration. At this time, use the shear mode

Piezoelectric ceramics can measure the acceleration parallel to the piezoelectric plate surface.

4. Application in underwater acoustic equipment

This is an extremely important application field of piezoelectric ceramics. Underwater acoustic equipment refers to equipment that uses sound waves to transmit information to complete underwater observation, communication, and detection. Electromagnetic waves attenuate little when propagating in the air, and attenuate greatly in water, so radar and radio equipment cannot be used to observe, communicate and detect underwater. The error of sound waves in water is small, so the above-mentioned purposes are realized by means of the propagation of sound waves in water.The use of piezoelectric ceramic urn materials to manufacture the components of underwater acoustic equipment is of great use, such as marine geological survey, seabed geological exploration, sea chart compilation, channel dredging and port engineering, submarine cables and guiding fishery operations, seabed and underwater targets And facility detection and identification.

5. Application in ultrasound equipment

Such instruments include ultrasonic cleaners, ultrasonic motors, ultrasonic microphones, ultrasonic pulse diagnostic devices, ultrasonic atomizers, ultrasonic microscopes, etc. For example, ultrasonic flaw detectors detect flaws in materials and concrete components, use ultrasound to detect brain and heart diagnosis, obstetrics and pregnancy diagnosis.

6. Application of Piezoelectric Filter

Such applications include bulk acoustic wave filters and surface acoustic wave filters. The vibration mode and the transmission mode of the vibration wave of the bulk acoustic wave filter are both bulk acoustic wave, and this type of device is called the bulk acoustic wave filter. If the vibration mode and vibration wave transmission method are both surface acoustic waves, this type of device is called a surface acoustic wave filter.

Acoustic bulk wave devices include energy trapping mode piezoelectric ceramic devices, piezoelectric ceramic resonators, piezoelectric tuning forks, piezoelectric retarders, and so on. Surface acoustic wave devices include surface acoustic wave retarders, surface acoustic wave resonators, and surface acoustic wave amplifiers.

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