Modern electronics uses many elements whose operation is based on the interaction of electric current and magnetic fields. The article will give a detailed description of what a Hall sensor is, what types of sensors exist and why it is used in cars.
A connection diagram and a method for testing such sensors in various ways will also be provided.
Hall effect
The discoverer of the phenomenon of the formation of an electric potential difference during the interaction of a magnetic field and an electric current was physicist Edwin Hall. He did a simple experiment with a gold plate. The experiment was carried out as follows:
- The edges of the golden square plate were marked with the letters A, B, C, D.
- An electric current source was connected to faces “D” and “B”.
- The energized plate was placed between two magnets.
- When the plate interacted with a magnetic field, an electric current with a very small voltage appeared on faces “A” and “C”.
This effect is based on a simple physical law: when the Lorentz force acts on a charge carrier, a potential difference is formed at its terminals.
The simplest Edwin Hall effect sensor was not used until the use of elements made of germanium, silicon and other compounds that can interact with a magnetic field.
Educational program: the operating principle of a brushless motor
As an illustration, I will take a very common motor with twelve coils in the stator and fourteen magnets in the rotor. There are quite a few options for winding and the number of coils/magnets, but the essence always remains the same. Here is a photo of my copy from both sides, both the coils and the magnets in the rotor are clearly visible:
To make it even clearer, I drew a diagram of it, the poles of the rotor magnets are indicated by color, red for the north and blue for the south:
Don’t pay attention to the hall sensors for now, they’re not there anyway
