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Shutter (photography) In photography, a shutter is a device that allows light to pass for a determined period, exposing photographic film or a photosensitive digital sensor to light in order to capture a permanent image of a scene. A shutter can also be used to allow pulses of light to pass outwards, as seen in a movie projector or a signal lamp.
Detectivity: The square root of the detector area divided by the noise equivalent power. Gain: The output current of a photodetector divided by the current directly produced by the photons incident on the detectors, i.e., the built-in current gain. Dark current: The current flowing through a photodetector even in the absence of light.
Specific detectivity. Specific detectivity, or D*, for a photodetector is a figure of merit used to characterize performance, equal to the reciprocal of noise-equivalent power (NEP), normalized per square root of the sensor's area and frequency bandwidth (reciprocal of twice the integration time). Specific detectivity is given by , where is the ...
A suppressor or silencer is a device either attached to or part of the barrel of a firearm to reduce the amount of noise and flash generated by firing the weapon. It generally takes the form of a cylindrically shaped metal tube with various internal mechanisms to reduce the sound of firing by slowing the escaping propellant gas, and sometimes ...
Jodrell Bank Observatory. / 53.23625°N 2.3071388888889°W / 53.23625; -2.3071388888889. Jodrell Bank Observatory ( / ˈdʒɒdrəl / JOD-rəl) in Cheshire, England hosts a number of radio telescopes as part of the Jodrell Bank Centre for Astrophysics at the University of Manchester. The observatory was established in 1945 by Bernard ...
Detection. In general, detection is the action of accessing information without specific cooperation from with the sender. In the history of radio communications, the term "detector" was first used for a device that detected the simple presence or absence of a radio signal, since all communications were in Morse code. The term is still in use ...
The Personnel Detection Device (PDD), produced by Saab, is a type of vest which the soldier wears during exercise. The vest contains detectors that record hits and misses from laser operated weapons. Detectors can also be placed on the soldiers’ helmets. When soldiers participate in military exercises their actions can be recorded.
Fano noise. Fano noise is a fluctuation of an electric charge obtained in a detector (in spite of constant value of the measured quantity, which is usually an energy), arising from processes in the detector. It was first described by Ugo Fano in 1947, [1] as a fluctuation of amount of ion pairs produced by a charged particle of high energy in a ...