Ultrasonic transducer or ultrasonic sensor is a type of acoustic sensor that is divided into three broad categories: transmitter, receiver and transceiver. The transmitter converts the electrical signal into an ultrasound, the receiver converts the ultrasound into an electrical signal, and the transceiver can transmit and receive ultrasound.
In a similar way to radar and sonar, ultrasonic transducers are used in systems that evaluate targets by interpreting reflected signals. For example, by measuring the time between sending a signal and receiving an object's distance echo can be calculated. Passive ultrasonic sensors are essentially microphones that detect ultrasonic sounds that are present under certain conditions.
Ultrasonic probes and ultrasonic baths apply ultrasonic energy to drive particles in various materials; See Sonication .
Video Ultrasonic transducer
Apps and performance
Ultrasound can be used to measure wind speed and direction (anemometer), tank or channel fluid level, and speed through air or water. To measure speed or direction, the device uses multiple detectors and calculates the velocity from the relative distance to the particles in air or water. To measure the liquid level of the tank or channel, and also the sea level (tide gauge), the sensor measures the distance (start) to the liquid surface. Further applications include: moisturizer, sonar, medical ultrasound, burglar alarm, non-destructive testing and wireless charging.
Systems typically use transducers that produce sound waves in ultrasonic range, above 18 kHz, by converting electrical energy into sound, then after receiving echoes convert sound waves into measurable and displayed electrical energy.
This technology is limited by surface shape and density or material consistency. Foams, in particular, can distort surface-level readings.
This technology, too, can detect objects that are close to and track their positions.
Maps Ultrasonic transducer
Transducers
The ultrasonic transducer turns the air conditioner into an ultrasound, and vice versa. Ultrasonic, usually refers to piezoelectric transducers or capacitive transducers. Piezoelectric crystals change size and shape when voltage is applied; The AC voltage makes them oscillate at the same frequency and produce ultrasonic sound. The capacitive transducer uses an electrostatic field between the conductive diaphragm and the back plate.
The transducer emission pattern can be determined by the active transducer area and shape, ultrasound wavelength, and propagation media sound speed. The diagram shows the sound field of focused and focused ultrasonic transducers in water, evident at different energy levels.
Because piezoelectric materials produce voltages when forces are applied to them, they can also work as ultrasonic detectors. Some systems use separate transmitters and receivers, while others combine the two functions into a single piezoelectric transceiver.
Ultrasound transmitters can also use non-piezoelectric principles. such as magnetostriction. Materials with this size change property a little when exposed to a magnetic field, and make the transducer practical.
The capacitor microphone ("condenser") has a thin diaphragm that responds to ultrasound waves. The electric field change between the diaphragm and the close-range backing plate converts the sound signal into electric current, which can be amplified.
The principle of the diaphragm (or membrane) is also used in relatively new micro-machine ultrasonic transducers (MUTs). This device is made using silicon micro-machining technology (MEMS technology), which is very useful for the manufacture of transducer arrays. The diaphragm vibration can be measured or electronically induced using the dielectric capacitance between the diaphragm and the closely spaced backing plate (CMUT), or by adding a thin layer of piezo-electric material to the diaphragm (PMUT). Or, recent research has shown that the vibration of the diaphragm can be measured by a small optical ring resonator integrated in the diaphragm (OMUS).
Use in medicine
Medical ultrasonic transducers (probes) come in many different shapes and sizes to use in creating cross-sectional images of various body parts. The transducer can pass through the surface and come in contact with the body, or inserted into the body organs such as the rectum or vagina. Doctors who perform ultrasound guided procedures often use probe positioning systems to withstand ultrasonic transducers.
Air detection sensors are used in a variety of roles. Non-invasive air detection is for the most critical situations where patient safety is mandatory. Many variables, which can affect the performance of sensing systems based on amplitude or sustainability, are eliminated or greatly reduced, resulting in accurate and repeatable detection.
One of the main principles in this technology is that the transmission signal consists of a brief burst of ultrasonic energy. After each exploded, electronics look for a signal back in a small window of time that corresponds to the time it takes for energy to pass through the ship. Only signals received during this period will be eligible for additional signal processing. This principle is similar to radar range gating.
Use in industry
Ultrasonic sensors can detect target movements and measure the distance to them in many factories and automated processing plants. Sensors can have digital output on or off to detect object movement, or analog output proportional to distance. They can feel the tip of the material as part of the web guide system.
Ultrasonic sensors are widely used in cars as parking sensors to assist drivers in reversing to parking spaces. They are being tested for a number of other automotive uses including ultrasonic person detection and assist in autonomous UAV navigation.
Because ultrasonic sensors use sound rather than light for detection, they work in applications where photoelectric sensors may not. Ultrasonic is a great solution for detecting clear objects, clear label detection and for fluid level measurement, applications that struggle with photoelectricity due to target translucence. In addition, the target or reflect color does not affect the ultrasonic sensor, which can operate reliably in high-spot environments.
Passive ultrasonic sensors can be used to detect high pressure gas or leakage of liquids, or other hazardous conditions that produce ultrasonic sound. In this device, audio from the transducer (microphone) is converted to the human auditory range.
High power ultrasonic transmitters are used in commercially available ultrasonic cleaning devices. The ultrasonic transducer is attached to a stainless steel pan filled with a solvent (often water or isopropanol). An electric square wave feeds the transducer, creating a sound in a solvent strong enough to cause cavitation.
Ultrasonic technology has been used for several cleaning purposes. One that gets a decent amount of traction in the last decade is the ultrasonic gun cleaning.
Ultrasonic testing is also widely used in metallurgy and techniques for evaluating corrosion, welds, and material defects using different types of scanning.
References
Source of the article : Wikipedia
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