The Hall sensor is an indispensable device in a car. Its action is based on an interesting phenomenon discovered in 1879 by the American physicist E. Hall. Subsequently, this phenomenon was named after him.
Hall sensor working principle
The operation of such a sensor is based on the Hall effect. It consists in the following: if a semiconductor, along which an electric current flows, is placed in a magnetic field, a transverse potential difference (voltage) will appear. This voltage is called the Hall voltage. It can range from tens of microvolts to hundreds of millivolts. At the time of the discovery of the Hall effect, there was no industrial application for it. Only 75 years later, thin semiconductor films were invented that possessed the desired properties. With their help, the Hall sensor was created.
The first such sensor consisted of a permanent magnet, a rotor blade, magnetic circuits, a microcircuit and two leads. He had a lot of merit. It was very easy to manage. When a signal is applied to its inputs, a rectangular pulse, constant in time, appears, without sharp jumps. This sensor had small dimensions (on the order of a micrometer). Like any microcircuit, it had its drawbacks: sensitivity to changes in the electric field and too high a price.
Hall sensors can be analog and digital. The former are used to convert the induction of a magnetic field into voltage. Digital ones determine the presence or absence of a field in a given area. If the field induction reaches a certain value, the output of the sensor will be a logical unit, if it does not reach a logical zero. Both analog and digital sensors sense the transverse potential difference that occurs when a magnetic field is applied to a current-carrying semiconductor.
Hall sensor applications
Initially, the Hall sensor was used in the automotive industry. With its help, the angle of the crankshaft or camshaft position is determined. In older vehicles, it is used to generate a spark signal.
Hall sensors are widely used in the manufacture of ammeters capable of detecting currents from 250 mA to thousands of amperes. With the help of sensors it is possible to measure the strength of direct and alternating current of high frequency. In this case, it will be proportional to the magnetic induction, which is induced by the current passing through the conductor.
Hall sensors are used in the manufacture of electromechanical drives, special systems for ensuring the operation of actuators in factories and plants. In this case, the sensors will adjust the correct position of the mechanism.
