| 摘要 |
A smoke detector unit (20) comprising a housing containing a smoke detector (24) and at least two component mounting boards, such as printed circuit boards, in a stacked arrangement, the housing having at least one air gap (34), wherein one of the boards (36) is inverted with respect to the other and the detector is positioned on the lower board whereby, in use, the detector extends upwardly between the boards. The housing may be in the form of a ceiling rose. |
