摘要 |
There is disclosed a security enclosure including a folded, flexible, electrically insulating sheet extending over the whole of the area of the enclosure and carrying lines of electrically responsive material on each side, the lines defining a conductor extending over both sides of the sheet, electrical connections between lines on one side of the sheet and respective lines on the other side of the sheet being provided by line connections extending through the sheet and at selected edges of the sheet the line connections being spaced inwardly of the edge and separated from the edges by a respective line-carrying portion of sheet. The enclosure includes a circuit for detecting a change in an electrical characteristic of the conductor caused by an attempt to penetrate the sheet.
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