| 摘要 |
A security enclosure comprises a first layer of an insulating material 16 extending over the whole of the area of the enclosure and carrying a linear electrically responsive element 18 on at least one surface. A low tensile strength layer 32 having lower cohesion than adhesion is located between the first layer of insulating material and the electrically responsive element. A second layer of insulating material 22 is adhered to and covers the electrically responsive element. The element is arranged in a configuration on the surface so dividing the surface that attempted penetration of the enclosure changes an electrical characteristic of the element, the change being detectable by an electrical circuit 50. An attempt to remove the second layer of insulating material to gain access to the element results in breakup of the low tensile strength layer and thus damage to the element and produces a detectable change in an electrical characteristic of the element. <IMAGE>
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