A walk-through metal detector operates by using electromagnetic fields to detect the presence of metal objects on an individual's body. Here's a basic explanation of how it works:

Transmitter Coils: The metal detector contains two sets of coils – transmitter coils and receiver coils. The transmitter coils generate a magnetic field when electricity passes through them.

Eddy Currents: When a person walks through the metal detector, the magnetic field induces electric currents, known as eddy currents, in any nearby metal objects.

Disturbance in Magnetic Field: The presence of metal disrupts the magnetic field created by the transmitter coils. The larger and more conductive the metal object, the greater the disruption.

Receiver Coils: The receiver coils, positioned parallel to the transmitter coils, detect the disturbances in the magnetic field caused by the eddy currents in the metal objects.

Signal Processing: The metal detector's electronic system processes the signals from the receiver coils. If the disruption in the magnetic field exceeds a certain threshold, an alarm is triggered, indicating the presence of metal.

In summary, a walk-through metal detector identifies metal objects by detecting changes in the magnetic field induced by those objects. The system is designed to distinguish between harmless items, like coins or jewelry, and potentially more significant metal objects that may pose a security risk.