According to different structures, smoke detectors can generally be divided into ion-type smoke detectors, photoelectric smoke detectors and so on. The ion-type smoke detector works by ionizing the radioactive source of the ionized chamber, Mei Am241, the positive and negative ions produced by ionization, and each moves toward the positive and negative electrodes under the action of the electric field. Under normal circumstances, the current and voltage of the internal and external ionization chamber are stable, but when a fire occurs, there is smoke rushing into the outer ionizing chamber, interfering with the normal operation of charged particles, it will make the current, voltage change, destroy the balance between the internal and external ionization chamber, in the detection of the ionization chamber at both ends of the voltage increase to a certain value, The detector senses this, and the switch circuit action transmits the alarm message.
The photoelectric smoke detector is composed of light source, photoelectric element and electronic switch, which uses the principle of light scattering to detect the smoke generated in the early stage of the fire and sends out the alarm signal in time. It works by using a light emitting element and a photosensitive element, which is usually the light emitted by the light emitting element, which is beamed through a lens to the photosensitive element, and the circuit remains normal. If there is smoke from the barrier, the light reached on the photosensitive element will be significantly reduced, so the light-sensitive element will change the light force into a change in current, through the amplification circuit to send an alarm signal.
It can be seen that whether it is ion-type smoke detector, or photoelectric smoke detector, are by the sensing elements, detection circuits, communication circuits and other major components. And these three important components, because of its optical, physical and electrical characteristics, will inevitably be affected by the external environment and its own defects, resulting in false positives and false positives of the detector. Therefore, in use, in order to avoid as much as possible with the smoke detector false positives and false positives, it is necessary to take corresponding measures to avoid external interference factors and the detector's own defects in the situation.
Life, should pay attention to the smoke alarm in time, will fire to prevent problems before they occur.
