History of Hall Sensors
In 1879, Edwin Hall discovered the Hall effect.
In his experiment, he placed a strip of conducting material in between magnet poles with the magnetic field lines being perpendicular to the strip surface plane.
Hall observed that there is a voltage developed perpendicular to the current flowing direction and concluded that the magnetic field exerted forces on the flowing electric charge.
How does it work?
The Lorentz Force
When a charged particle (e.g. electron) moves through a magnetic field, it experiences a force perpendicular to its traveling velocity and the magnetic field direction. This force is known as the Lorentz force.
The Lorentz force is described by the following relation:
F = q(v x B)
Where q is the charge of the particle, v is the electron velocity, B is the magnetic field, and F is the resulting force felt by the electron under the influence of a magnetic field.
The Hall effect
As an electric current flows through a conducting material in the presence of a magnetic field, the magnetic field induces the Lorentz force upon the moving electrons.
This deflection of electrons results in the accumulation of electrons on one side of the conductor, thereby inducing a potential difference between both sides of the conductor. This potential difference can be measured and is known as the Hall voltage.