What is the difference between Ionization or Optical smoke detectors?

Answer 1

The other answers all have some elements of truth.

Ionization-type smoke detectors utilize a radioactive source to establish a current between two electrodes. Smoke particles (and some other things) interfere with ion mobility, and reduce the current. At some level, the detector goes into alarm.

Photoelectric-type detectors utilize a light source and a photosensitive element, placed so that it doesn't see the light. Smoke particles scatter the light so the photosensitive element sees light from the particles. Just as you can see dust particles in sunlight.

Photoelectric-type detectors are best for almost all conditions, and especially the home. Some knowledgeable experts think ionization-type smoke detectors should be outlawed for home use, because of the differences in detecting ability for home fires.

Answer 2

Heat can definitely make some smoke detectors go off. I have hard wired detectors in my home that will go off if you walk under them right out of a hot shower on a cool morning. Not the best way to wake up the rest of the house!

Answer 3

Both rely on the process of missing pulse detection. The presence of smoke prevents either light or ionizing radiation from an emitting source from reaching the detector. If a missing pulse is detected, the alarm sounds.

Dust can cause a problem if it builds up on the light source or photo detector. This technology appeases the people who want nothing to do with radioactivity, and is cheaper to manufacture.

Answer 4

Ionisation type are more sensitive to fast flaming fires with little or no smoke. Optical are more suited to smouldering fires with large smoke particles, bedding, furniture rtc.

Answer 5

one uses a Light dependent anatomic eye the other uses Beta Radiation particles.