MULTIPLE-USE DEACTIVATION DEVICE FOR ELECTRONIC ARTICLE SURVEILLANCE MARKERS

摘要

A single deactivation device (10) is used to deactivate both harmonic type E AS markers and magnetomechanical type EAS markers. The deactivation device includes a housing (12), a permanent magnet (14) and a coil (16) disposed within the housing. The coil is circular and is arranged concentrically with , and outside of, the permanent magnet. The permanent magnet forms a DC magnet ic field for deactivating the harmonic type marker by magnetizing control elements thereof. The coil is driven to generate an AC magnetic field that deactivates the magnetomechanical type marker by degaussing a control elemen t thereof. The maximum amplitude of the AC magnetic field is lower than the level of the DC magnetic field, and is substantially below the coercivity of the control elements of the harmonic type marker. The coercivity of the control element of the magnetomechanical type marker is low enough to be degaussed by the AC magnetic field.