People can hear that the sound is generated by the vibration of the object. Its frequency is in the range of 20HZ-20KHZ. Ultrasonic waves above 20KHZ are called ultrasonic waves, and those below 20HZ are called infrasound waves. Commonly used ultrasonic frequencies are tens of KHZ-tens of MHZ.
Ultrasonic is a mechanical oscillation in an elastic medium. There are two forms: lateral oscillation (transverse wave) and longitudinal oscillation (longitudinal wave). In industrial applications, longitudinal oscillations are mainly used. Ultrasonic waves can travel in gases, liquids, and solids at different propagation speeds. In addition, it also has refraction and reflection phenomena and decays during propagation. Ultrasonic waves are transmitted in the air at a low frequency, generally tens of KHZ, while frequencies are higher in solids and liquids. It decays faster in the air and propagates in liquids and solids with less attenuation and longer propagation. By using the characteristics of ultrasonic waves, various ultrasonic sensors can be made, and different circuits can be used to make various ultrasonic measuring instruments and devices, and are widely used in various fields such as communication and medical home appliances.
The main materials of the ultrasonic sensor are piezoelectric crystal (electrostrictive) and nickel-iron aluminum alloy (magnetostrictive). The electrostrictive material is lead zirconate titanate (PZT) or the like. An ultrasonic sensor composed of a piezoelectric crystal is a reversible sensor that converts electrical energy into mechanical oscillation to generate ultrasonic waves, and when it receives ultrasonic waves, it can also be converted into electrical energy, so it can be divided into a transmitter or a receiver. Some ultrasonic sensors are used for both transmission and reception. Only small ultrasonic sensors are introduced here. The transmission and reception are slightly different. It is suitable for propagation in air. The working frequency is generally 23-25KHZ and 40-45KHZ. These sensors are suitable for ranging, remote ultrasonic sensors
Control, anti-theft and other purposes. Such species are T/R-40-16, T/R-40-12, etc. (where T represents transmission, R represents reception, 40 represents a frequency of 40 kHz, and 16 and 12 indicate their outer diameter dimensions in millimeters). There is also a sealed ultrasonic sensor (MA40EI type). It is characterized by its waterproof function (but it cannot be placed in water) and can be used as a material level and proximity switch. Its performance is better. There are three basic types of ultrasonic applications, such as remote control, anti-theft alarm, automatic door, proximity switch, etc.; separate reflection type for distance measurement, liquid level or material level; reflective type for material flaw detection, thickness measurement, etc. .
It consists of a transmitting sensor (or wave transmitter), a receiving sensor (or wave receiver), a control part and a power supply part. The transmitter sensor consists of a transmitter and a ceramic vibrator transducer with a diameter of about 15 mm. The transducer functions to convert the electrical vibration energy of the ceramic vibrator into super energy and radiate into the air; and the receiving sensor is a ceramic vibrator transducer. Comprising with the amplifying circuit, the transducer receives the wave to generate mechanical vibration, converts it into electric energy, and uses it as the output of the sensor receiver to detect the transmitted ultrasonic signal. In actual use, the ceramic vibrator used as the transmitting sensor is also used. It can be used as a ceramic vibrator for receiver sensors. The control part mainly controls the pulse chain frequency, duty cycle, sparse modulation and counting, and detection distance sent by the transmitter.
Hangzhou Success Ultrasonic Equipment Co.,Ltd.
Add：No.16,Shangsong South Street, Shouxiang Town, Fuyang, Hangzhou, Zhejiang, China (Mainland)