What Is an Ultrasonic Generator?
Ultrasonic waves are airborne vibrations with a frequency of 20 kilohertz or higher, and they are sounds that cannot be felt by humans.
To produce these ultrasonic waves, it is necessary to vibrate an object at a high frequency and vibrate the air around the object. Commonly used are what are called piezoelectric elements.
This is based on the property known as the piezoelectric effect, where a piezoelectric element stretches or shrinks when a voltage is applied to it, depending on the polarity of the voltage.
When an AC voltage is applied from an electrode connected to the piezoelectric element, the element vibrates at a high speed due to the piezoelectric effect, generating ultrasonic waves.
Uses of Ultrasonic Generators
Ultrasonic generators are used in a wide range of applications, from everyday situations to industrial fields.
For example, they can be used to produce emulsions or prepare samples or pigments in liquids containing liquid or solid particles.
Ultrasonic waves are often used in academic and industrial fields to clean mechanical and electronic parts.
In humidifiers, ultrasonic generators are used to atomize the liquid to produce a mist.
Principle of Ultrasonic Generators
The piezoelectric elements used in ultrasonic generators are a type of ceramic made from materials such as titanium oxide or barium oxide, which are baked and hardened at high temperatures.
One characteristic of these elements is that when pressure is externally applied, a voltage is generated within the element.
The reason for voltage generation, when pressure is applied to a solid, is due to the distortion of the crystal structure in the solid caused by the pressure.
Positive and negative ions are arranged within the solid, and external forces distort the positions of these ions, resulting in a charge bias within the solid.
As a result, electrical polarization occurs, generating voltage within the solid.
Conversely, it can be understood that the crystal structure changes due to the application of voltage, and the position of the ions is altered by the electric field, resulting in a change in the thickness of the solid.
When a high-frequency AC voltage is applied to this piezoelectric element, the element rapidly expands and contracts, producing longitudinal waves (sound) at high speed, which are emitted as ultrasonic waves.