| 摘要 |
<p>The relatively simple burglar alarm network which triggers when any one of a number of contacts in a security circuit is broken, and is suitable for protecting doors, windows, jewellery cases and the like. It comprises an alarm, typically a siren, a long wire incorporating a number of contacts (14, 15) in series and mounted at the locations requiring protection, and a central control circuit (17). The entire security circuit incorporates a number of switches in the central control, the security circuit itself, the alarm, and a return circuit, and contains two multiway switches for setting up the circuit and for checking. The interconnections required for securing a house, including the parallel arrangement required to allow authorized access, are also included.</p> |
