| 摘要 |
<p>The burglar alarm consists of a battery driven alarm clock fitted with an additional counter and connection socket for an alarm cable. One end of the latter carries a plug for the alarm clock socket while the other one carries a switch, preferably in the form of a wedge-shaped contact element, responsive to the pressure exerted by door opening, which actuates its triggering. The switch may be in the form of a double plug whose two halves may be secured to the door frame and the door leaf respectively by adhesive tapes.</p> |
