Magnetism sensor is magnetism or changeover of magnetism encode information telegraphic date, so that pass electronic circuit,undertake handling.

 

 

Magnetism sensor is solid state equipment, they become more and more popular, because they can be used at the application of a lot of different types, feel for example measure the place, speed or directional motion. They also are the sensor choice of a kind of popularity of electronic design personnel, because they have blame contact to not have,wear away operation, low safeguard, solid design and equipment of sealed suddenly Er effect, do not suffer vibration, the influence of dirt and water.

 

One of main use of magnetism sensor are to be used at feeling to measure the place, be apart from the car system with speed. For example, the angle position of brace axis is used at the ignition angle of sparkplug, car seat and the position that are used at safety belt of seat of safe gasbag pilot or the wheel rate that are used at preventing to adopt dead brake system detect (ABS) .

 

Magnetism sensor design is used at answering all sorts of different application medium all sorts of enjoying magnetic field, the magnetism sensor of a kind of type, its output signal is his all round the function of magnetic field density, call sensor of suddenly Er effect.

 

Sensor of suddenly Er effect is the equipment that activations by exterior magnetic field. We know magnetic field has two main character: Magnetic flux density, (B) with polarity (arctic and antarctic) . The output signal of sensor of suddenly Er effect is parts of an apparatus all round the function of magnetic field density. When the magnetic flux density all round sensor exceeds a certain to establish threshold value beforehand, sensor detects it produces the output tension that calls V H of suddenly Er voltage. See next pictures please.

 

Principle of sensor of suddenly Er effect

 

 

Sensor of suddenly Er effect basically is comprised by material of a thin rectangular P semiconductor, for example arsenic changes gallium (GaAs) , antimony changes indium (InSb) or arsenic changes indium (InAs) , they carry the electricity with successive oneself. Place when parts of an apparatus when magnetic field is medium, magnetic flux line applies thrust augmentation on semiconductor material, this force makes electric load flows child, electron and hole deflexion arrive semiconductor board either side. Electric load flows child the result that this kind of motion is the magnetic force that they pass semiconductor material place to endure.

 

When these electrons and hole shift side, flow through these electric load child accumulate voltage arises between the two side of semiconductor material. Next, the electron is become the influence of orthogonal exterior magnetic field with its through the motion of semiconductor material, and this is planted the effect is bigger in compressed and rectangular material.

 

The result that produces measurable tension through using magnetic field is called what 18 centuries discover its suddenly Huadehuoer after 70 time suddenly Er effect, the elementary physics principle of suddenly Er effect is Luoluncili. Span in order to arise the magnetic flux line with the poor electromotive force that narrates device must perpendicular, (the flow of the electric current that 90 ø goes to) , and according to correct polarity, normally of an antarctic.

 

Suddenly Er effect provides the information of type of concerned magnetic pole and magnetic field size. For example, antarctic meeting brings about parts of an apparatus to generate voltage output, and arctic is invalid. Normally, when existing without magnetic field, sensor of suddenly Er effect and switch are to be in “ to close ” position by the design (open circuit condition) . “ just turns into to put through when they are enduring the magnetic field of enough strength and polarity only ” , (closed circuit condition) .

 

Sensor of magnetism of suddenly Er effect

 

The output voltage of basic Huoer component (call Huo Er voltage, (V H) ) with the magnetic field intensity that passes semiconductor data (output αH) into direct ratio. This output voltage is very OK small, although also be had a few small hot season only by strong magnetic field, because this is most,business uses parts of an apparatus of suddenly Er effect is to pass inside buy dc amplifier, logistic switch circuit and manostat make, in order to heighten the sensitivity of sensor, lag and output voltage. This also makes sensor of suddenly Er effect can be below more extensive power source and magnetic field condition the job.

 

Sensor of suddenly Er effect

 

 

Sensor of suddenly Er effect offers linear or digital output. Linear (imitate) the output signal of sensor takes the output from operation amplifier directly, output voltage and the magnetic field that carry suddenly Er sensor become direct ratio. Voltage of this output suddenly Er is as follows:

 

 

Linear or imitate sensor offer successive voltage output, its increase as strong magnetic field, and be reduced as weak magnetic field. In sensor of effect of linear output suddenly Er, as the addition of magnetic field intensity, the output signal of amplifier also can increase, begin the limitation that saturated power source brings to bear on till it. Any additional magnetic field increase to won’t produce an effect to output, but can make its more saturated.

 

On the other hand, the number outputs sensor to have Schmidt trigger, buy lag receives operation amplifier repeatedly inside. When the flux that carries suddenly Er sensor establishs a value beforehand more than, the output of parts of an apparatus shuts ” in its “ sudden switch puts through to “ between condition ” condition and the contact that does not have any types rebounds. When sensor immigrant and move when giving magnetic field, this kind inside any oscillation that buy lag eliminated output signal. Next digital output sensor has two kinds of state only, “ON” and “OFF” .

 

The sensor of effect of digital suddenly Er that has two kinds of basic kinds, ambipolar with sheet extremely. Ambipolar sensor needs magnetic field (antarctic) will operate them, a negative magnetic field (arctic) release them, and sheet pole sensor needs a magnetic antarctic to operate and release domain of magnetic field of their pass in and out only.

 

Parts of an apparatus of effect of most suddenly Er cannot direct switch is big electric load, because their output drive capacity is very small, about 10 to 20mA. Laden to big electric current, open a way of a collector (electric current is absorbed) NPN transistor adds output end.

 

This transistor absorbs switch job as NPN inside its saturation area, the “ON” of prep above of magnetic flux density that should bring to bear on only establishs a point beforehand, can make output end weak point to receive the land.

 

Outputting switch transistor can be to open type to blast off extremely transistor, transistor of open circuit collector is configured or both offers push-pull output configuration, its can absorb enough electricity with direct drive a lot of load, include relay, electromotor, LED and lamp.

 

Suddenly Er effect applies

 

Sensor of suddenly Er effect activations by magnetic field, and be in a lot of application, this device can arrive by join the operation of individual permanent magnet of mobile axis or device. The magnet that has a lot of different kinds moves, for example “ front ” , “ flank ” , “ push-pull ” or “ are pushed – push the inductive motion such as ” . To the configuration of every kinds of type, to ensure the greatest sensitivity, magnetic flux line must perpendicular from beginning to end the inductive area at equipment, and must have correct polarity.

 

Same to ensure linear, need the magnet of intensity of tall magnetic field, its produce a big strong change to needs exercise. Have campaign use at detecting magnetic field a few possible way, and below be two use the sense with single commonner magnetic body to measure configuration: The head puts through detect and sideways detects.

 

The front detects

 

 

Just as its name implies, “ front detects effect of perpendicular Yu Huoer travels ” requirement magnetic field move plant, and to detect, it faces towards mobile face is close to sensor directly. The method of ” of front of a kind of “ .

 

This kind of front is close to a method to produce output signal V H, its show magnetic field strength in linear device, magnetic flux density, as the function of the distance that is far from sensor of suddenly Er effect. Magnetic field is closer, magnetic field is accordingly stronger, output voltage is bigger, vice versa.

 

Linear parts of an apparatus is OK still and divisional magnetic field and negative magnetic field. Can make nonlinear device sets place of air gap distance to spark beforehand in what be far from magnetic body output “ON” detects with indicating the position.

 

Side direction detects

 

 

The 2nd passing feeling configuration is “ side direction detects ” . This need has moved magnet with the means of transverse motion the surface of Huoer component.

 

Side direction or slip through detecting it is to be used at detecting the existence of magnetic field, inside the air gap distance that because it has moved,the face of suddenly Er component secures for example, computation rotates it is useful that the rotate speed coming back of magnetic body or electromotor is spent.

 

Depend on the position when magnetic field passes the 0 centers line of sensor, can produce the linear that expresses to be being outputted and lose output to output voltage. This allows directional shift to detect, its can be perpendicular also can be a level.

 

Sensor of suddenly Er effect has a lot of different application, be close to sensor especially. They can replace optics and smooth sensor to use, ambient conditions includes water, oscillatory, bilge or oil, for example car application. Parts of an apparatus of suddenly Er effect also can be used at electric current to detect.