Smoke detectors are devices that sense smoke as an indicator of fire. They work by detecting small particles in the air using different technologies. There are two basic types of smoke detectors: photoelectric and ionization. Some detectors use both sensing methods for maximum protection.
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Photoelectric detectors: These detectors aim a light source into a sensing chamber at an angle away from the sensor. When smoke enters the chamber, it reflects light onto the sensor, triggering the alarm.
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Ionization detectors: These detectors use a small amount of radioactive material to ionize the air inside the sensing chamber. When smoke enters the chamber, it disrupts the ionization process, triggering the alarm.
Smoke detectors can be sensitive enough to detect almost any smoke, but this can result in nuisance alarms from things like cooking or dust. Less sensitive detectors may not go off in time during an actual fire. Smoke detectors are usually connected to a central fire alarm system in commercial and industrial buildings.
In summary, smoke detectors detect smoke particles in the air using photoelectric or ionization technology, or a combination of both.
