Question: Why must you be careful with orientation when you use the hall effect probe to measure magnetic field?
Background: In a recent Physics 2 lab, we used a magnetic field sensor which I'm guessing is also a "Hall Effect Probe" because my professor said it was the same thing.
I know that the Hall effect is where electrons moving through material are effected by a "Lorentz Force" that acts perpendicularly. I know that the electrons will essentially bend with more electrons to the right of the material then on the left
I also know that the Size of the Voltage is directly proportial to the size of the electric current and the strength of the magnetic field
Yet, I don't understand the question in regards to orientation?
I looked here and wiki, and found nothing in regards specifically to orientation except that the 'hall probe is placed between magnetic pole pieces'
Any help or advice would be great, thanks in advance.
Best Answer
The Hall effect is always at right angles to a current flow, and a Hall sensor typically has two electrodes that sense the effect (the Hall voltage) and which are located 'left' and 'right'. But there's no effect for B field component parallel to the current flow, and the electrodes' position 'left' and 'right' establish a second direction which is also a B field orientation that generates no effect (there's only Hall voltage perpendicular to the B direction).
So, a Hall sensor will only detect ONE COMPONENT, one directional part, of the full three-dimensional vector B field. A Hall sensor doesn't tell the magnitude of the B field vector. It gives magnitude and direction (sign) of one of the three components of B.