Hall effect

Definition

The Hall effect describes the production of a voltage difference (the Hall voltage) across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current. This phenomenon is used to measure magnetic fields and carrier density in materials.

5 Must Know Facts For Your Next Test

1. The Hall effect was discovered by Edwin Hall in 1879.
2. The Hall voltage is directly proportional to the strength of the magnetic field applied.
3. Hall coefficient ($R_H$) can be positive or negative depending on whether charge carriers are positive (holes) or negative (electrons).
4. Applications of the Hall effect include Hall effect sensors, which are used for proximity sensing, positioning, speed detection, and current sensing.
5. In semiconductors, the sign of the Hall coefficient indicates whether electrons or holes are the majority carriers.

Review Questions

• How does the orientation between electric current and magnetic field affect the Hall voltage?
• What information can be determined from measuring the Hall voltage in a material?
• Why is the sign of the Hall coefficient important in semiconductor physics?

Related terms

Magnetic Flux Density:

The amount of magnetic flux through a unit area perpendicular to the direction of magnetic flow; measured in teslas (T).

Lorentz Force:

The force exerted on a charged particle moving through an electric and a magnetic field; given by $\mathbf{F} = q(\mathbf{E} + \mathbf{v} \times \mathbf{B})$.

Conductivity:

A measure of a material's ability to conduct electric current; reciprocal of resistivity.