Copyright © Klaus Piontzik  
German Version 
In order to be able to measure magnetic fields, a physical effect
is required that reacts to magnetic flux density B. The Hall effect provides such a phenomenon. 
Illustration 6.1.1 – Hall sensor 
As shown in Illustration 6.1.1, a very thin metal plate is flowed through
by a current Ix that is evenly distributed over its cross section. No voltage
can be detected between two points A and B, which are equidistant from the power
supply lines and which are connected to a galvanometer.
If the plate is passed through by a magnetic field B, the Lorentz force F acts on the moving charge carriers of the primary current I. This force eliminates the uniform charge distribution in the plate and leads to a potential difference U_{H} between the two points A and B. It flows a current through a galvanometer connected to these points. The charge distribution caused by the Lorentz force creates an electric field with field strength E, which counteracts the deflection of the charge carriers. A state arises in which the Lorentz force F_{L} and the counterforce F_{E} caused by the electric field have the same amount. The general equation for the Hall voltage can be derived from these boundary conditions: 
6.1.1 Equation 
Where R_{H} is the Hall coefficient and d the material thickness
of the metal plate are to be viewed as specific constants of a Hall sensor, which are summarized in a constant k Then we can generally write: 
6.1.2 Equation 
The Hall voltage only depends on the supply current I_{B} of the sensor and the flux density B
of the acting magnetic field. The Hall sensor is operated with a direct voltage, i.e. I is constant.
In this configuration, the Hall sensor is normally used as a magnetic flux density meter. 
200 sides, 23 of them in color 154 pictures 38 tables Production und Publishing: ISBN 9783735738547 Price: 25 Euro 
