16 Facts About Hall effect

Hall effect is the production of a voltage difference across an electrical conductor that is transverse to an electric current in the conductor and to an applied magnetic field perpendicular to the current.

Hall effect can occur across a void or hole in a semiconductor or metal plate, when current is injected via contacts that lie on the boundary or edge of the void or hole, and the charge flows outside the void or hole, in the metal or semiconductor.

Hall effect coefficient is defined as the ratio of the induced electric field to the product of the current density and the applied magnetic field.

Eighteen years before the electron was discovered, his measurements of the tiny Hall effect produced in the apparatus he used were an experimental tour de force, published under the name "On a New Action of the Magnet on Electric Currents".

Hall effect is due to the nature of the current in a conductor.

The result is an asymmetric distribution of charge density across the Hall effect element, arising from a force that is perpendicular to both the straight path and the applied magnetic field.

One very important feature of the Hall effect is that it differentiates between positive charges moving in one direction and negative charges moving in the opposite.

Simple formula for the Hall effect coefficient given above is usually a good explanation when conduction is dominated by a single charge carrier.

In ferromagnetic materials, the Hall resistivity includes an additional contribution, known as the anomalous Hall effect, which depends directly on the magnetization of the material, and is often much larger than the ordinary Hall effect.

The anomalous Hall effect can be either an extrinsic effect due to spin-dependent scattering of the charge carriers, or an intrinsic effect which can be described in terms of the Berry phase effect in the crystal momentum space .

Nevertheless, when the Hall effect parameter is low, their motion between two encounters with heavy particles is almost linear.

Hall effect devices produce a very low signal level and thus require amplification.

When Hall effect is compared to photo-sensitive methods, it is harder to get absolute position with Hall effect.

For example, a Hall effect sensor integrated into a ferrite ring can reduce the detection of stray fields by a factor of 100 or better .

Hall effect devices used in motion sensing and motion limit switches can offer enhanced reliability in extreme environments.

Applications for Hall effect sensing have expanded to industrial applications, which now use Hall effect joysticks to control hydraulic valves, replacing the traditional mechanical levers with contactless sensing.