Hall Voltage

Definition

Hall voltage is an electrical potential difference generated transversely across a conductor or semiconductor material when it carries an electric current and is placed in a perpendicular magnetic field. This phenomenon is known as the Hall effect and is used in various applications, such as magnetic field sensors and Hall-effect switches.

5 Must Know Facts For Your Next Test

1. The Hall voltage is proportional to the strength of the magnetic field, the electric current, and the charge carrier density in the material.
2. The sign of the Hall voltage indicates the type of charge carriers (positive or negative) responsible for the current flow.
3. The Hall effect is used in Hall-effect sensors to measure the strength of magnetic fields, which can be used to detect the position, speed, and direction of moving objects.
4. The Hall effect is also used in Hall-effect switches, which can be used to detect the presence or absence of a magnetic field and trigger an electronic circuit.
5. The Hall coefficient, which is the ratio of the Hall voltage to the product of the current and the magnetic field, is a material-specific property that can be used to determine the type and density of charge carriers in a material.

Review Questions

• Explain the relationship between the Hall voltage, the electric current, and the magnetic field in the Hall effect.
  • The Hall voltage is directly proportional to the strength of the applied magnetic field and the electric current flowing through the conductor or semiconductor material. When a current-carrying material is placed in a perpendicular magnetic field, the Lorentz force acting on the charge carriers causes them to deflect to one side of the material, creating a transverse potential difference known as the Hall voltage. The magnitude of the Hall voltage is determined by the strength of the magnetic field, the current, and the charge carrier density in the material.
• Describe how the Hall effect can be used to determine the type and density of charge carriers in a material.
  • The sign of the Hall voltage indicates the type of charge carriers (positive or negative) responsible for the current flow. If the Hall voltage is positive, the charge carriers are predominantly positive (such as holes in a p-type semiconductor). If the Hall voltage is negative, the charge carriers are predominantly negative (such as electrons in an n-type semiconductor). Additionally, the Hall coefficient, which is the ratio of the Hall voltage to the product of the current and the magnetic field, is a material-specific property that can be used to determine the density of charge carriers in the material. By measuring the Hall coefficient, the type and density of charge carriers can be inferred, which is useful in the characterization of semiconductor materials.
• Analyze the applications of the Hall effect in devices such as Hall-effect sensors and Hall-effect switches, and explain how the Hall effect is utilized in these applications.
  • The Hall effect is widely used in the design of Hall-effect sensors and Hall-effect switches. Hall-effect sensors utilize the Hall voltage generated by a current-carrying material in a magnetic field to measure the strength and direction of the magnetic field. This allows them to be used for position, speed, and direction sensing in various applications, such as in the detection of the crankshaft or camshaft position in automotive engines. Hall-effect switches, on the other hand, use the Hall effect to detect the presence or absence of a magnetic field, which can be used to trigger electronic circuits. For example, Hall-effect switches can be used in computer keyboards, door alarms, and other devices that require magnetic field-based switching. The ability to detect and measure magnetic fields through the Hall effect makes these devices invaluable in a wide range of industrial and consumer applications.

Related terms

Hall Effect: The Hall effect is the production of a voltage difference (the Hall voltage) across an electrical conductor, transverse to an electric current in the conductor and to an applied magnetic field perpendicular to the current.

Lorentz Force: The Lorentz force is the combination of electric and magnetic force on a point charge due to electromagnetic fields. It is the force exerted on a charged particle when it moves through a magnetic field.

Charge Carriers: Charge carriers are the particles within a material that are responsible for the flow of electric current. In metals, the charge carriers are typically electrons, while in semiconductors, they can be both electrons and holes.