Ultrasonic transducers send and receive waves for many types of sensing. Examples include distance, proximity, level, nondestructive evaluation, web break detection, counting, and security applications. They typically operate at their resonant frequency with various construction options, beam patterns, and power levels.
Ultrasonic transducers have many critical specifications. Transmitting frequency is the usable frequency range of the device. Bandwidth is the difference between low and high operational frequency limits. Rated signal power available from transducer is another important specification. Transmit sensitivity is the ratio of sound pressure produced to input voltage. Receive sensitivity is the ratio of output voltage produced over sound pressure sensed. The beam angle is the total included angle of ultrasonic beam. In general, a high frequency transducer will produce a narrow beam and a lower frequency transducer a wider beam. The beam angle can be influenced somewhat by the transducer housing construction.
Ultrasonic transducers send and receive waves for many types of sensing. Examples include distance, proximity, level, nondestructive evaluation, web break detection, counting, and security applications. They typically operate at their resonant frequency with various construction options, beam patterns, and power levels.
Ultrasonic transducers have many critical specifications. Transmitting frequency is the usable frequency range of the device. Bandwidth is the difference between low and high operational frequency limits. Rated signal power available from transducer is another important specification. Transmit sensitivity is the ratio of sound pressure produced to input voltage. Receive sensitivity is the ratio of output voltage produced over sound pressure sensed. The beam angle is the total included angle of ultrasonic beam. In general, a high frequency transducer will produce a narrow beam and a lower frequency transducer a wider beam. The beam angle can be influenced somewhat by the transducer housing construction.
Ultrasonic transducers come in different styles for different applications. Plain general-purpose transducers, including air transducers, are available with no specialized features. More specialized styles are common as well, such as contact transducers for placing directly on the surface to be measured. Dual element transducers have two elements in the transducer housing and allow the transmitter and receiver to operate independently. The elements are angled toward each other to create a reflective transmit/receive pathway. Angle beam transducers include mounted transparent angle blocks and are often used for weld inspection and flaw detection. They typically utilize refracted shear waves to detect flaws throughout the depth of welded areas. Immersible transducers are designed to be totally submerged in a liquid medium, most often fresh water. The protected element style has the transducer element protected for use on rough surfaces. Delay line transducers are versatile, often with replaceable head options such as membranes and wear caps. They are used to gage or detect flaws such as delaminations in thin materials. Shear wave transducers introduce shear waves into material without using an angle beam wedge. The ratio of shear wave components to longitudinal components can exceed 30dB. Medical style transducers and housings are designed for specific medical applications.
Common features available for ultrasonic transducers are array configuration for connecting more than one transducer in series or parallel; temperature compensation circuitry that compensates for sensitivities changing with ambient temperature; and optional analog output. Most transducers output analog voltage, but may have provisions for current loop output, etc.
