| 摘要 |
PROBLEM TO BE SOLVED: To easily adjust the sensitivity of a photoelectric smoke sensor, and to easily compensate (control) the temperature characteristics of the photoelectric smoke sensor at the time of manufacturing the photoelectric smoke sensor. SOLUTION: A physical variable detecting part 21 is provided with a light emitting circuit 31 and a light receiving circuit 32 which receives scattered light, due to smoke, of the light emitted from the light emitting circuit 31. In this case, the light emitting circuit 31 is constituted by connecting a switching element and a load resistance with a light emitting element, and when the switching element is a bi-polar transistor, the base voltage is controlled based on control from a CPU 24, and when the switching element is a field effect transistor, the gate voltage is controlled based on control from the CPU 24 so that emission currents can be adjusted.
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