| 摘要 |
PURPOSE: A live cable access alarm apparatus and method are provided to prevent unnecessary frequent alarm according to entrance and breakaway at the boundary neighborhood of alarm start distance. CONSTITUTION: A live cable access alarm apparatus(100) comprises a selection terminal(110), an antenna(120), a filter unit(130), and a comparator(150). The selection terminal is selected a usage voltage. The filter unit filters a live cable voltage in the electromagnetic waves existing in atmosphere. The comparator compares the usage voltage with the live cable voltage. An alarm outputs an alarm signal according to electric field strength of the live cable voltage when the live cable voltage exceeds the usage voltage. |
