Such a device as the Hall sensor is a magnetoelectric mechanism, the principle of which was first discovered by the physicist Hall, after whom he was later named. In this article we will tell you what a Hall sensor is, what its basic principles of work are, how this device works in a mobile phone and a car. You will also learn about the main types of such units.
- 1 Basic principles of operation of Hall sensors
- 2 The use of Hall sensors for mobile phones and other equipment
- 3 Hall Sensor Classification
- 4 Features of the use of the Hall sensor in the car
- 5 How to check the Hall sensor yourself
- 6 Features of the use of Hall sensors
Basic principles of operation of Hall sensors
The principle of operation of the device lies in the presence of a member of the title, which is associated with the electrical circuit.
The Hall sensor itself is such microcircuit capable of creating this or that informational signal. A fixed magnetic field is the basis of the principle of operation of this mechanism. To determine the speed of movement of the fixed elements of a particular structure, a Hall sensor and magnets are attached to it to the moving part.
Also, moving contacts and parts can simply be magnetized and there will be no need to supplement the design with anything. BUT several permanent magnets are needed to measure the rotational speed and the Hall sensor itself. In this case, the principle of operation of this device will be as follows:
- in the free state the plate will move between the two poles;
- it will also shield the magnetic field;
- during each turn there will be an electrical impulse in the tachometer.
And in order to increase the accuracy of the indicators, you need to increase the number of magnets used.
The use of Hall sensors for mobile phones and other equipment
The device can produce the following signal states:
- unit when signal is present (LED lit);
- zero at its absence and an extinct LED.
This feature of the issuance of the signal made this device an indispensable element for mobile phones and other digital equipment. Sensors can be placed in the same housing with logic elements and microcontrollers, as well as cling directly to them.
Examples of using this device for phones and equipment are:
- in mobile phone This device is needed to control the closure of the cover, it shows whether the magnetic clasp is open or closed. Also in the old clamshell phones, he is responsible for turning off the screen when the lid is closed;
- if you close the laptop coverthen we will see that its screen goes out. This is also the work of the device. It is installed on the motherboard, and on the cover of the laptop there is a small magnet. When the lid closes, the magnetic field is triggered by the sensor and the screen goes out.
These instruments are also very widely used. electric motors and in cars as position sensors, we will tell about it in more detail later.
Hall Sensor Classification
This device works in tandem with a magnetic field. It is divided into two main categories:
An analog device is capable of processing induction into voltage, and the amount it is able to show depends on the polarity of the magnetic field and the force. Also consider the distance of its installation.
Thanks to digital devices can you determine if there is a field.
They work like this:
- The sensor will issue a logical unit, subject to the induction of the desired threshold.
- If the threshold is not reached, then a logical zero is issued.
- If the induction is weak and the device has a low sensitivity, then it is possible not to fix the field.
A huge drawback of a digital device is the presence of an insensitive inter-threshold zone.
Digital devices, in turn, are divided into two categories of bipolar:
- bipolar hall sensorsable to respond to a change in the polarity of the magnetic field. So, one polarity turns off the device, and the other turns it on;
- unipolar may be included only in the presence of a certain polarity do they turn off when induction decreases.
Features of the use of the Hall sensor in the car
In the car, the Hall sensor works on the principle of a conventional key - a contactor and a disconnector. The magnet rotates in the distributor and affects the sensor itself fixed in a stationary way. When the latter begins to "feel" the magnetic field, it begins to give impulses, which, in turn, cause a spark to ignite.
For a car, the Hall sensor is one of the key elements of its ignition system and is present in any model, regardless of configuration and cost.
Sometimes this device can be used in digital car speedometers or tachometers, as well as used to check the speed of movement of the gear data and to control the operation of the anti-lock system of the machine.
In addition, this unit is highly reliable. He is able to work far more than one year, and breaks down, as a rule, due to strong physical impact or due to heavy pollution. Very often sensor is installed so that it can be easily removed and replaced at any time.. The only exceptions are devices that are used to monitor the most complex automotive systems.
How to check the Hall sensor yourself
There are several methods to check the validation of the device for health. Each of them you can apply yourself depending on certain circumstances:
- tester check. To do this, you need any digital format tester, set the voltmeter mode on it and measure the voltage on the sensor with it. If the sensor is working properly, the voltage will range from 0.2 to 3 Volts. In the absence of it, or an indicator of more than 3 Volts, the sensor requires urgent replacement;
- verification by the device working by analogy with the device. Instead of the Hall sensor itself, which should be checked for operability, use a similarly working device. You can create such a device yourself. Take a small piece of wire and a block along with the distributor. Such a construction cannot be used for a long time, especially in a car, but for one time an exception can be made. This will tell you if your problem was in the sensor, or something else;
- check with the new device. You can put another Hall sensor, whose work does not cause you complaints and check the second.
Features of the use of Hall sensors
If such a device is used in a construction site, then it must be carefully monitored. Keep in mind frequent and regular checks as well as preventive measures for the circuit that is responsible for the connection.
When servicing, try not to spoil the design of the device. Therefore, in order to prevent its damage, disconnecting the device from the power supply must be made after turning off the ignition. Due to this, you will not allow current drops, respectively, the device will not break.
Non-working units in most cases do not repair, because in practice, repair is completely useless. A broken device is simply disposed of, and a new one is put in its place.
The key advantage of Hall sensors is that, subject to the permissible operating values of the current and voltage, on a huge number of on and off phones, smartphones, laptops and other appliances. Unlike the reed switch, there are no electromechanical contacts in the device that wear out quickly.
So, we briefly talked about what a Hall sensor is, how it works, and what function it is able to perform in cars, as well as mobile phones and other types of digital technology.