What is the white semicircle on the roof of a hotel room? It's lit with a small red light.

The smoke detector has radioactive source americium 24 1 in the inner and outer ionization chambers, and the positive and negative ions generated by ionization move to the positive and negative electrodes respectively under the action of electric field. Under normal circumstances, the current and voltage of the inner and outer ionization chambers are stable.

Once the smoke escapes from the ionization chamber outside and interferes with the normal movement of charged particles, the current and voltage will change and destroy the balance between the ionization chamber inside and outside, so the wireless transmitter sends out a wireless alarm signal to inform the remote receiving host and transmit alarm information.

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Precautions:

1, the temperature detector should not be installed around the detector due to natural or working heat sources, which may reach the temperature where the detector is likely to cause false alarm. Therefore, attention should be paid to avoid the possibility that the detector directly receives solar radiation during installation, and the field equipment that can emit thermal radiation, hot air or hot steam should be considered and preventive measures should be taken.

2. In a low room with high air mobility, flying dust can easily enter the smoke detector, causing false alarm of fire. In this case, extra protective measures should be taken for the detector, such as special installation with proper shielding.

3. Smoke or similar aerosol generated in the working process will cause the detector to malfunction. Therefore, attention should be paid not to install smoke detectors in workplaces and equipment parts that may cause aerosol accumulation.

4, infrared beam smoke detector should avoid strong sunlight or infrared radiation source, the installation of the transmitter and receiver must be fixed, not loose, should avoid violent vibration, on the beam axis should avoid fixed shelter and mobile shelter.

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