Piezo Speaker 41mm 20KHz 95dB

Piezo Speaker 41mm 20KHz 95dB

The sound of the piezo speaker is outside the hearing range of the human ear, that is, at a frequency above 20KHZ. Mainly used in bird repellent, dog repellent, rat repellent and other fields.

Ultrasound is a mechanical wave whose frequency is higher than 16KHz, which exceeds the frequency range of ordinary people’s hearing. A sound wave is a mechanical wave. When its vibration frequency is in the range of 20Hz-20KHz, the human ear can feel it, which is called audible sound wave.

Mechanical vibrations with a frequency lower than 20 Hz cannot be felt by the human ear, and are called infrasound waves, but many animals can feel them. For example, infrasound waves before an earthquake can cause abnormal reactions in many animals. Waves with a frequency between 3108-31011 Hz are called microwaves. Ultrasound has many characteristics different from audible sound waves.

Ultrasonic waves have good directivity and concentrated energy, so they have great penetrating power and can penetrate steel plates several meters thick without much energy loss. Ultrasonic waves have a great ability to penetrate liquids and solids, especially in solids that are opaque to sunlight. It can penetrate to a depth of tens of meters. When the ultrasonic wave hits the impurity or the interface, it will produce a significant reflection and form an echo, and it can produce a Doppler effect when it hits a moving object.

Ultrasonic waves have good directivity and concentrated energy, so they have great penetrating power and can penetrate steel plates several meters thick without much energy loss. Ultrasound has a great ability to penetrate liquids and solids, especially in solids that are opaque to sunlight. It can penetrate to a depth of tens of meters. When the ultrasonic wave hits the impurity or the interface, it will produce a significant reflection and form an echo, and it can produce a Doppler effect when it hits a moving object.