Ultrasonic wave is a kind of mechanical oscillation in elastic medium, there are two forms: transverse oscillation (shear wave) and longitudinal oscillation (longitudinal wave). Longitudinal oscillation is mainly used in industry. Ultrasonic wave can be transmitted in gas, liquid and solid, and its propagation speed is different. In addition, it also has refraction and reflection phenomenon, and in the propagation process has attenuation. In the air, the transmission of ultrasound, the frequency is low, generally dozens of khz, and in solids, liquids, the frequency is higher. Decay in the air faster, but in the liquid and solid propagation, attenuation is smaller, spread far. Using the characteristics of ultrasonic, can be made of a variety of ultrasonic sensors, with different circuits, made into a variety of ultrasonic measuring instruments and devices, and in the communication, medical appliances and other aspects of the wide application.
By sending a sensor (or call wave transmitter), receiving sensor (or wave receiver), control part and
Power supply components. Transmitter sensor by the transmitter and the use of the diameter of 15mm ceramic vibrator Transducer, the role of the transducer is the ceramic oscillator of the electrical vibration energy into the super energy and radiation to the air; the receiving sensor is composed of a ceramic vibrator transducer and a amplifying circuit, and the receiving wave of the transducer generates mechanical vibration and transforms it into electrical energy as the output of the sensor receiver. To detect the sent hyper. In practice, the ceramic oscillator of the transmitter sensor can also be used as the ceramic vibrator of the receiver sensor. The control part mainly controls the pulse chain frequency, the duty ratio, the sparse modulation, the counting and the detection distance of the transmitter.