A smoke detector is a device that detects smoke, typically as an indicator of fire. Commercial, industrial, and mass residential devices issue a signal to a fire alarm system, while household detectors, known as smoke alarms, generally issue a local audible or visual alarm from the detector itself.
Smoke detectors are common household items. One type, ionization smoke detectors, uses a small radioactive source as a key component in detecting smoke particles. Photoelectric smoke detectors use a light and sensor to detect smoke. Ionization smoke detectors are more effective at detecting flash fires, while photoelectric smoke detectors are more effective in detecting smoldering fires. Both cost about the same, and many smoke detector models use both ionization and photoelectric features to achieve maximum detection.
Remember Always use a smoke detector in your home!
Never take an ionizing smoke detector apart.
What you can do to protect yourself