Patent ID: 7834761

Claim:
An apparatus for activating, deactivating or reactivating an electronic article surveillance (EAS) tag comprising: an H-bridge circuit adapted to be coupled to a current source for applying current to the H-bridge circuit; and an antenna coupled to the H-bridge circuit such that current can flow through the antenna in at least a first and second direction, wherein the H-bridge circuit is configured to direct an increasing current flow through the antenna in the first direction, thereby generating a positive increasing magnetic field from the antenna; wherein the H-bridge circuit is configured to direct a decreasing current flow through the antenna in the first direction, thereby generating a positive decreasing magnetic field from the antenna; wherein the H-bridge circuit is configured to direct an increasing current flow through the antenna in the second direction such that current flow through the antenna reverses, thereby generating a negative increasing magnetic field from the antenna; and wherein the H-bridge circuit is configured to direct a decreasing current flow through the antenna in the second direction, thereby generating a negative decreasing magnetic field from the antenna.