Photoelectric smoke detectors use a light beam and a sensor to detect smoke particles in the air. When smoke enters the chamber of the detector, it scatters light, which is then detected by the photoelectric sensor, triggering an alarm. This type of detector is particularly effective at detecting smoldering fires that produce larger smoke particles.
Here is a more detailed explanation put together for you by anka security:
How it works:
Light source:
Photoelectric smoke detectors contain a light emitting diode (LED) that shines a light beam into a small chamber.
Photosensitive cell:
The photosensitive cell (also called a photodiode or photocell) is at an angle to the light beam, so it does not normally receive the light from the LED.
Smoke detection:
When smoke enters the chamber, the smoke particles scatter the light from the LED. Some of this scattered light strikes the photosensitive cell.
Alarm activation:
The increased light on the photosensitive cell triggers an electronic circuit, which then activates the alarm.
Advantages of photoelectric smoke detectors:
Effectiveness against smoldering fires:
Photoelectric detectors are generally more effective than ionization detectors at detecting slow smoldering fires, which produce larger smoke particles.
Fewer false alarms:
They are also less prone to false alarms from cooking or steam, as these do not typically produce the same types of smoke particles that scatter light.
Limitations:
Less effective against fast-burning flames:
Photoelectric detectors react more slowly to fast-burning flames, which produce less smoke but more heat.
Potential nuisance alarms:
While less prone to false alarms than ionization detectors, they can still be triggered by dust or insects in the room.
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