A smoke detector is an essential life-safety device designed to sense the presence of smoke as an early indicator of fire. Most units utilize either ionization or photoelectric sensors to detect combustion particles and trigger a high-decibel audible alarm. By providing an early warning, these devices give occupants critical time to evacuate the premises safely before a fire spreads. Modern smoke detectors can also be interconnected, ensuring that if one unit senses danger, all alarms throughout the building sound simultaneously for maximum coverage.