Smoke detectors are devices that detect smoke in a space. They are typically found in buildings, such as homes and offices, where fire is a potential hazard. Smoke detectors consist of a sensor to detect smoke, a sounder, an amplifying circuit, and a power supply. When smoke is detected by the sensor, the alarm is activated, alerting people to evacuate or take steps to fight the fire. Smoke detectors are usually powered by batteries or are connected to the building’s electrical system. Some models also include a radio transmitter that can be used to alert the fire department or other emergency services. Smoke detectors are an inexpensive and simple way to help protect against the dangers of fire.