| 摘要 |
A photoelectric smoke sensor using light scattering or attenuating effects to detect smoke caused by a fire comprises a source (1) radiating light into a smoke detection space (3), a detector (4) receiving light attenuated or scattered by smoke in the smoke detection space, and detection circuitry (5, 6) for detecting a change in output of the light detection element, the detection circuitry including a device (6) for compensating the detector output for any change in an ambient temperature. The compensating device (6) may comprise a thermistor (Th) and amplification system having a temperature characteristic which balances that of the source (1) and detector (2). <IMAGE> |
