When was the photoelectric smoke detector invented and listed?
Photoelectric smoke detectors were invented in the late 70s. Photoelectric and ion are two detectors with different operating principles.
Ionic: magnesium 241 as a material, the principle is to use the smoke produced by fire particles to reduce its conductivity and alarm.
It is divided into light scattering type and scattering type.Shading type: it is irradiated to the photosensitive element, and is converted into an electrical signal, so that the whole circuit is in a normal state, and no alarm occurs. When a fire smoke exists when the light emitted from the light absorption and scattering by smoke particles, the propagation characteristics of light intensity change, receiving the photosensitive element is weakened, the normal state is the alarm circuit.Scattering type: no smoke, the light can not be transmitted to the photosensitive element, the circuit is maintained in a normal state. When there is fire, there is smoke,Light passes through the reflection or scattering of smoke particles to the photosensor, and the light signals are converted into electrical signals. After amplification, the circuit is enlarged. Driving alarm device and sending out fire alarm signal.
The photoelectric smoke detector consists of light source, photoelectric component, electronic switch and labyrinth cavity chamber.Working principle: the principle of light scattering is used to detect smoke in the early stage of fire, and alarm signal is sent out in time.It is divided into light scattering type and scattering type.Shading type: it is irradiated to the photosensitive element, and is converted into an electrical signal, so that the whole circuit is in a normal state, and no alarm occurs. When a fire smoke exists when the light emitted from the light absorption and scattering by smoke particles, the propagation characteristics of light intensity change, receiving the photosensitive element is weakened, the normal state is the alarm circuit.
