Metal detectors

Definition

Metal detectors are devices that use electromagnetic fields to detect the presence of metallic objects. They operate based on the principles of electromagnetic induction and eddy currents.

5 Must Know Facts For Your Next Test

1. The primary working principle of metal detectors is electromagnetic induction.
2. When a metal detector's coil generates an alternating magnetic field, it induces eddy currents in nearby metallic objects.
3. The induced eddy currents create their own magnetic fields, which can be detected by the receiver coil of the metal detector.
4. The sensitivity and depth of detection depend on factors such as coil size, frequency, and the electrical conductivity of the metal.
5. Metal detectors often use both transmit (TX) and receive (RX) coils to distinguish between different types of metals.

Review Questions

• What physical principle allows metal detectors to detect metallic objects?
• How do eddy currents contribute to the functioning of a metal detector?
• What factors influence the sensitivity and depth of detection in a metal detector?

Related terms

Electromagnetic Induction: The process by which a changing magnetic field within a conductor induces an electric current.

Eddy Currents: Circulating currents induced within conductors by changing magnetic fields, often responsible for energy dissipation.

Self-Inductance: The property of a coil or circuit whereby a change in current induces an electromotive force (EMF) within itself.