Ultrasonic sensor: Ultrasonic Sensor One, Brief Introduction of the Principle： The ultrasonic sensor is the sensor that uses the ultrasonic
characteristics to make.The ultrasonic wave is one kind of
mechanical wave which the vibration frequency is higher than the
sound wave.The ultrasonic wave comes from the vibration caused
stimulation under the voltage from the Wafer of the ultrasonic
transducer. The ultrasonic wave has these following advantages :high frequency,
short wave length ,small diffraction, especially in those
advantages :good directivity thus can be ray which it runs in
directional propagation.The ultrasonic wave can easily pass through
the liquid, the solid, especially can pass through several tens m
in depth for the solid which not transparent. When the ultrasonic meets impurity or division surface, it will
reflect remarkably thus forms into echo wave. If the ultrasonic
meets something moving, it will produce Doppler effect. So the
ultrasonic measurement is widely used in industry, national
defense,biomedical fields and so on. If uses the ultrasonic to be
as measurement method, there must be some certain device which can
produce and receive the ultrasonic wave. That device with the function is called ultrasonic sensor or
habitually ultrasonic transducer or ultrasonic probe. The ultrasonic probe mainly consists of piezoelectric substrate ,
which can give out the ultrasonic wave also can receive the
ultrasonic wave. The low power ultrasonic probe is mainly used in
detection. The low power ultrasonic probe has many different
structures :straight probe (vertical wave),angle probe(horizontal
wave),surface wave probe(surface wave),Lamb wave(Lamb wave), double
probes(One is for reflection, another is for receiver) ect. The core part of the ultrasonic probe is its piezoelectric
substrate which is in plastic cover or metal cover.There are many
material can make piezoelectric substrate. If piezoelectric
substrate small or big such as the diameter or thickness not same
thus every ultrasonic probe is not same with their performance.
Before our using them, we should know more about their
performances. The main performances of the ultrasonic probe,
including: (1)Work frequency: It’s the resonance frequency of piezoelectric
substrate. While putting the frequency of AC voltage of two sides
same with the resonance frequency of piezoelectric substrate, the
output power is maximum and the sensitivity is highest. (2)Working temperature: because the curie point of piezoelectric
material is much higher, especially the power of ultrasonic probe
for diagnosis is very low thus the working temperature is very low.
So it can work for long time but not out of work. The working
temperature of most of ultrasonic probes for medical use is very
high thus needs the special refrigeration equipments. (3)The sensitivity: It mainly depends on making technology. If the
sensitivity is very high, can reduce transmit power, increase
distinguish rate, increase measurement distance. Two: Main Applications The ultrasonic distance sensor can be mainly used in material
position monitoring(liquid position monitoring), preventing to be
hit for the Roberts , all kinds of ultrasonic approaching levels
and theft and alarm fields ect. Its reliable working, easy
installation, waterproof type, small joint angle, high sensitivity,
easy to connect to industry display meters. We also supply the
ultrasonic probe with bigger joint angle. 1,Ultrasonic measurement distance meter: The principle for supersonic technique is very easy to understand:
In the air when the sound move the air to send the information, if
the sound meets something is small or big, soft or hard, it will
accordingly produce the echo. We use the ultrasonic sensor to
receive the sound of the echo, accordingly calculate the time
difference from emission to rebounding, with the help of the sound
speed, we may know the distance between you and something is in
front of you. According to the sound of the echo is strong or weak, we may know
something is big or small. This is the principle for the ultrasonic
measurement in the air. By the ultrasonic measurement distance, we may detect the liquid
position, object position(storage capacity), flow of open channel,
approaching switch. It’s widely used in chemical industry, electric
industry, metallurgy, coal mine, wharf , water treatment, light
industry, and food industry and so on . 2,Ultrasonic | 
