What are hall components?

What is a hall component?

Hall component is a kind of magnetic sensor based on Hall effect, which can detect the magnetic field and its change, and can be used in various magnetic field related occasions. Hall element has many advantages, such as firm structure, small volume, light weight, long service life, convenient installation, low power consumption, high frequency (up to 1MHz), vibration resistance, and no fear of dust, oil, water vapor and salt spray pollution or corrosion.
Hall element is widely used, such as signal sensor in automobile distributor, speed sensor in ABS system, automobile speedometer and odometer, liquid physical quantity detector, current detection and working state diagnosis of various electrical loads, engine speed and crankshaft angle sensor, various switches, etc.

(common hall element, picture from Internet)

Hall effect (The working principle of the Hall element)

To understand the working principle of Hall element, let’s start with learning Hall effect.
Hall effect is a kind of electromagnetic effect, which was discovered by American physicist hall in 1879 when he studied the conductive mechanism of metal. When the current passes through the semiconductor perpendicular to the external magnetic field, the carrier will deflect, and an additional electric field will be generated perpendicular to the direction of the current and magnetic field, thus creating a potential difference at both ends of the semiconductor. This phenomenon is called Hall effect, which is also called Hall potential difference.

Fabrication Materials of Hall Elements

Hall elements can be made of a variety of semiconductor materials, such as GE, Si, InSb, GaAs, InAs, InAsP and multilayer semiconductor heterostructure quantum well materials.
In semiconductor, the electron mobility (average velocity of electron directional motion) is higher than that of hole mobility, so n-type semiconductor is more suitable for manufacturing Hall elements with high sensitivity.
The commonly used semiconductor materials are n-type silicon, n-type germanium, InSb, InSAS and in type solid solutions composed of different proportions of indium arsenite and Indium Phosphate.
Among them, n-type germanium is easy to process, and its hall constant, temperature performance and output linearity are good, so it is widely used. Because the hall constant of InSb is large at high temperature, its output is large, but it is most sensitive to temperature, especially in the low temperature range, the temperature coefficient is large; the hall constant of InSb is small, the temperature coefficient is small, and the output linearity is good; the temperature characteristics and output linearity of GaAs are also good Good linearity, ideal material, but expensive. Different materials are suitable for different occasions, InSb is suitable for sensitive elements, and germanium and indium arsenide Hall elements are suitable for measuring and indicating instruments.

Component classification of Hall element

According to the function of Hall elements, they can be divided into: Hall linear devices and Hall switching devices. The former outputs analog quantity, while the latter outputs digital quantity.
According to the properties of the detected objects, their applications can be divided into direct application and indirect application. The former is to directly detect the magnetic field or magnetic characteristics of the object to be detected, while the latter is to detect the artificially set magnetic field on the object to be detected, and use this magnetic field as the carrier of the detected information, through which many non electric and non-magnetic physical quantities, such as force, torque, pressure, stress, position, displacement, velocity, acceleration, angle, angular velocity, revolution, rotational speed and working speed, can be detected The time when the state changes, etc., is converted into electricity for detection and control.

Hall switch device

According to the induction mode of Hall switch, they can be divided into unipolar Hall switch, bipolar Hall switch and full polar hall switch.
The induction mode of unipolar Hall switch: a magnetic pole of the magnetic field is close to it and outputs a low potential voltage (low level) or off signal, while the magnetic pole of the magnetic field is away from it and outputs a high potential voltage (high level) or on signal. However, it should be noted that the unipolar Hall switch can only be effective when it specifies a magnetic pole induction, generally the S pole of the magnetic field is induced positively and the N pole is induced negatively.
Induction mode of bipolar Hall switch: because the magnetic field has two magnetic poles N and S (positive or negative), the two magnetic poles respectively control the opening and closing of bipolar Hall switch (high and low level). It generally has the function of locking, that is, when the magnetic pole leaves, the hall output signal does not change until the other magnetic pole induces. In addition, the initial state of bipolar Hall switch is random output, which may be high level or low level.
Induction mode of full polar hall switch: the induction mode of full polar hall switch is similar to that of unipolar Hall switch. The difference is that the unipolar Hall switch will specify the magnetic pole, while the full polar hall switch will not specify the magnetic pole. Any magnetic pole is close to the output low-level signal and away from the output high-level signal.

Hall linear device

Linear Hall element is a kind of magnetic sensor with analog signal output. The output voltage changes linearly with the input magnetic density.

The voltage output of linear Hall effect sensor IC can accurately track the change of magnetic flux density. In static state (without magnetic field), theoretically, the output should be equal to half of the supply voltage in the range of working voltage and working temperature. Increasing the south pole magnetic field will increase the voltage from its static voltage. On the contrary, increasing the north pole magnetic field will increase the voltage from its static voltage. These components measure the angle, proximity, motion and flux of the current. They can reflect mechanical events in a magnetically driven way.

Common models