A smoke detector has the capability to detect tiny particles of smoke rising from a smouldering object. It can raise an alarm and anticipate the possibility of fire breaking out. Smoke detectors can be one of two types. The first is an optical detector. This uses a light beam and sensor which reacts to anything that obscures the beam. The second type is the ionizing detector. This type can find smaller particles than its optical equivalent. The ionising detector is the one used almost universally.
The ionizing smoke detector consists of a detection chamber, where a low current of electricity flows around the air within. If smoke atoms enter, the chamber's resistance increases and causes less current to flow. A microchip in the device responds to the rapid drop in electrical current, by sounding the alarm.
