A smoke detector is a device that senses smoke as an indicator of fire. It works by using either ionization or photoelectric technology to detect smoke particles in the air. When smoke is detected, the device emits a loud alarm to alert occupants of a potential fire, allowing them to evacuate safely. Smoke detectors are commonly installed in homes, offices, and public buildings to enhance safety. Regular maintenance, such as testing the alarm and replacing batteries, is essential to ensure they function properly. Many models also include features like carbon monoxide detection for added protection against hazardous gases.