Views: 1 Author: Site Editor Publish Time: 2018-09-19 Origin: Site
The ultrasonic sensor is a sensor that is developed by using the characteristics of ultrasonic waves. Ultrasonic wave is a kind of mechanical wave with a vibration frequency which is higher than that of sound waves. It is generated by the vibration of the transducer wafer under the excitation of voltage. It has high frequency, short wavelength, small diffraction phenomenon, especially good directivity, and can be ray oriented. Ultrasonic waves have a great ability to penetrate liquids and solids, especially in the sunlight-opaque solids, which can penetrate depths of several tens of meters. When an ultrasonic wave hits an impurity or an interface, it will produce a significant reflection to form a reflection into an echo, which can produce a doppler effect when it hits a moving object. Therefore, ultrasonic testing is widely used in industrial, national defense, biomedical and other fields. Ultrasound is used as a means of detection, ultrasonic waves and ultrasonic waves must be generated. The device that performs this function is an ultrasonic sensor, customarily called an ultrasonic transducer, or an ultrasound probe.
The ultrasonic distance sensor circuit is mainly composed of a piezoelectric wafer, which can emit ultrasonic waves as well as ultrasonic waves. Small power ultrasound probes are used for detection. It has many different configurations, which can be divided into straight probe (longitudinal wave), oblique probe (transverse wave), surface wave probe (surface wave), Lamb wave probe (Lamp wave), dual probe (one probe reflection, one probe reception).
The core of the ultrasonic distance measurement transducer is a piezoelectric wafer in its plastic jacket or metal jacket. There are many kinds of materials constituting the wafer. The size of the wafer, such as diameter and thickness,it is also different, so the performance of each probe is different, we must know its performance before use. The main performance indicators of ultrasonic sensors include some aspects:
1.Working frequency
The operating frequency is the resonant frequency of the piezo ceramic wafer. When the frequency of the alternating voltage is applied to both ends thereof is equal to the resonant frequency of the wafer, the energy output is the largest and the sensitivity is also the highest. The working temperature is due to the fact that the curie point of the piezoelectric material is generally high, especially the diagnostic ultrasonic probe uses less power, so the operating temperature is relatively low, and it can work for a long time without failure. Medical ultrasound probes are relatively hot and require the separate equipment.
2. Sensitivity
