Abstract: Tagged articles are protected against theft by a system responding to articles having affixed thereto both a resonant circuit and a magnetizable strip. In one embodiment, a label alarm detector responds only to the presence of a resonant circuit or alternatively, only to the presence of a magnetizable strip. In a further embodiment, a label alarm detector responds to both presence of a resonant circuit and presence of a magnetizable strip.

Abstract: The method of producing an oscillating circuit on a label capable of being deactivated consists essentially of moving two surfaces of a capacitor together by a heated rod. Due to the heated rod dielectric material melts and the two capacitor surfaces become short circuited. Upon application of an appropriate current/voltage source, this short circuit is removed by burning or melting away to form a crater-like hole in a thinner surface of the capacitor. This produces a state of the label which allows, in a later deactivation step, a positive short circuiting. When the capacitor surfaces are moved together, the electrical connection between the two surfaces connects the crater forming source. Thereafter, a short circuit between the surfaces appears only when the label is passed through a deactivating station.