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A photoelectric, or optical smoke detector, contains a source of infrared, visible, or ultraviolet light—typically an incandescent light bulb or light-emitting diode (LED)—a lens, and a photoelectric receiver—typically a photodiode. In spot-type detectors, all of these components are arranged inside a chamber where air, which may contain ...
An optical beam smoke detector is a device that uses a projected beam of light to detect smoke across large areas, [1] typically as an indicator of fire. [2] They are used to detect fires in buildings where standard point smoke detectors would either be uneconomical [ 3 ] or restricted for use by the height of the building.
Manual fire alarm activation requires human intervention, as distinct from automatic fire alarm activation such as that provided through the use of heat detectors and smoke detectors. It is, however, possible for call points/pull stations to be used in conjunction with automatic detection as part of the overall fire detection and alarm system .
Ionization smoke alarms can quickly detect the small amounts of particles produced by fast-flaming fires, such as cooking fires or those fueled by paper or flammable liquids. A newer type of the smoke detector is the photoelectric smoke detector. It contains a light source, which is positioned indirectly to the light sensitive electric sensor.
A flame detector is a sensor designed to detect and respond to the presence of a flame or fire, allowing flame detection.Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line (such as a propane or a natural gas line), and activating a fire suppression system.
Stack light in automated production for in-line quality inspection. Stack lights (also known as signal tower lights, indicator lights, andon lights, warning lights, industrial signal lights, or tower lights) are commonly used on equipment in industrial manufacturing and process control environments to provide visual and audible indicators of a machine's status to machine operators, technicians ...
The basic signal consists of flashing red lights, a crossbuck and an alarm (either a bell, a speaker that mimics a bell sound or an electronic siren), attached to a mast. At most crossings, the signals will activate about 30 seconds before the train arrives but there are sensors measuring speed so that the crossing knows when to activate; so ...
The envelope detector has several drawbacks: The input to the detector must be band-pass filtered around the desired signal, or else the detector will simultaneously demodulate several signals. The filtering can be done with a tunable filter or, more practically, a superheterodyne receiver; It is more susceptible to noise than a product detector