Ionization smoke detectors operate because they have a small amount of radioactive material which is located in between two electrically charged plates. This ionizes the air which creates a current to flow in between the two plates. This flow of ions is disrupted when smoke enters the chamber. The reduction in the flow of current activates the alarm. Ionization smoke alarms tend to respond quicker than photoelectric smoke detectors to smoke that is produced from a flaming fire, although will not signal an alarm until a fire has become sufficient enough to produce enough smoke to reach the alarm.