Briefly what is the piezoelectric effect and the discovery of the piezoelectric effect

Views: 4 Author: Site Editor Publish Time: 2020-05-08 Origin: Site

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What is the piezoelectric effect

About piezoelectric effect,When a certain dielectric is deformed by an external force in a certain direction, polarization will occur inside it, and positive and negative charges will appear on its two opposite surfaces. When the external force is removed, it will return to the uncharged state. This phenomenon is called the positive piezoelectric effect. When the direction of the applied force changes, the polarity of the charge changes accordingly. Conversely, when an electric field is applied in the polarization direction of the dielectric, these dielectrics will also deform. After the electric field is removed, the deformation of the dielectric will disappear. This phenomenon is called the inverse piezoelectric effect PZT material piezo ceramic. A type of sensor developed based on the dielectric piezoelectric effect is called a piezoelectric sensor.

The piezoelectric body is polarized by the external mechanical force, and it causes bound charges with opposite signs in the two ends of the piezoelectric body. The charge density is proportional to the external mechanical force. This phenomenon is called positive piezoelectric effect. The piezoelectric body is deformed by the external electric field, and its deformation is proportional to the strength of the external electric field. This phenomenon is called the inverse piezoelectric effect. A solid with a positive piezoelectric effect must also have a reverse piezoelectric effect, and vice versa. The positive piezoelectric effect and the inverse piezoelectric effect are collectively called the piezoelectric effect. Whether piezo crystal has a piezoelectric effect is determined by the symmetry of the crystal structure.

The discovery of the piezoelectric effect

In 1880, the brothers Pierre Curie and Jacques Curie discovered that tourmaline had a piezoelectric effect. In 1881, they verified the inverse piezoelectric effect through experiments and obtained the forward and reverse piezoelectric constants. In 1984, the German physicist Vodmar Voigt (German: Woldemar Voigt) deduced that only crystals of the 20 midpoint group without a symmetric center may have a piezoelectric effect.

Current status of piezoelectric effect application
When you lightly press the button, the gas stove immediately ignited a blue flame. Have you ever realized what brought you this convenience? Connect a seemingly plain piezo disc transducer to the wire and the ammeter, and press it with your hand. The pointer of the ammeter also swings with it-is it a weird thing to produce a current? In fact, this is piezoelectric ceramics, a functional ceramic material that can convert mechanical energy and electrical energy to each other. What kind of material is piezoelectric ceramics? This is a pzt material with piezoelectric effect. The so-called piezoelectric effect refers to the deformation of some media under the action of force, which causes the surface of the media to be charged. This is a positive piezoelectric effect. Conversely, when an exciting electric field is applied, the medium will be mechanically deformed, called the inverse piezoelectric effect. This wonderful effect has been applied by scientists in many fields closely related to people's lives to achieve functions such as energy conversion, sensing, driving, frequency control, etc.

Piezoelectric ceramics have sensitive characteristics, which can convert extremely weak mechanical vibrations into electrical signals, and can be used in sonar systems, meteorological detection, telemetry environmental protection, household appliances, etc. Earthquakes are devastating disasters, and the source of the earthquake originated deep in the earth's crust. It was difficult to predict before, which put humanity into an embarrassing situation.

The deformation of piezoelectric ceramics under the action of an electric field is very small, at most not more than one ten millionth of its size. Don’t underestimate this small change. The precise control mechanism based on this principle-the piezoelectric driver. The control of precision instruments and machinery, microelectronics technology, bioengineering and other fields are all good news.

Frequency control devices such as resonators and filters are the key devices that determine the performance of communications equipment. Piezoelectric ceramics transducer have obvious advantages in this regard. It has good frequency stability, high accuracy and wide applicable frequency range, and is small, non-hygroscopic and long-lived. Especially in multi-channel communication equipment, it can improve anti-interference, so that the previous electromagnetic equipment cannot face its own face and is facing alternative fate.

Let's look at a new type of bicycle shock absorber. It is difficult for general shock absorbers to achieve a stable effect. This ACX shock absorber controller uses piezoelectric materials to provide a continuously variable shock absorber function for the first time. A ultrasonic sensor monitor the movement of the impact piston at a rate of 50 times per second. If the piston moves quickly, it is generally due to the rapid impact caused by driving on uneven ground. At this time, the maximum shock absorption function needs to be activated; if the piston moves slowly, then Indicates that the road surface is flat, and only weaker shock absorption functions are required. It can be said that although piezoelectric ceramics are new materials, they are quite civilian. It is used in high technology, but it is more for people's attention in life, creating a better life.