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Three photoresistors with scale in mm Large CdS photocell from a street light. A photoresistor is less light-sensitive than a photodiode or a phototransistor. The latter two components are true semiconductor devices, while a photoresistor is a passive component that does not have a PN-junction. The photoresistivity of any photoresistor may vary ...
Remote photoelectric sensors used for remote sensing contain only the optical components of a sensor. The circuitry for power input, amplification, and output switching is located elsewhere, typically in a control panel. This allows the sensor, itself, to be very small. Also, the controls for the sensor are more accessible, since they may be ...
Photodetectors may be used in different configurations. Single sensors may detect overall light levels. A 1-D array of photodetectors, as in a spectrophotometer or a Line scanner, may be used to measure the distribution of light along a line. A 2-D array of photodetectors may be used as an image sensor to form images from the pattern of light ...
Two different types of phototubes. A phototube or photoelectric cell is a type of gas-filled or vacuum tube that is sensitive to light. Such a tube is more correctly called a 'photoemissive cell' to distinguish it from photovoltaic or photoconductive cells.
2009 Nobel Prize in Physics laureates George E. Smith and Willard Boyle, 2009, photographed on a Nikon D80, which uses a CCD sensor. The basis for the CCD is the metal–oxide–semiconductor (MOS) structure, [2] with MOS capacitors being the basic building blocks of a CCD, [1] [3] and a depleted MOS structure used as the photodetector in early CCD devices.
Schematic diagram of an opto-isolator showing source of light (LED) on the left, dielectric barrier in the center, and sensor (phototransistor) on the right [note 1]. An opto-isolator (also called an optocoupler, photocoupler, or optical isolator) is an electronic component that transfers electrical signals between two isolated circuits by using light. [1]
PSDs can be divided into two classes which work according to different principles: In the first class, the sensors have an isotropic sensor surface that supplies continuous position data. The second class has discrete sensors in an raster-like structure on the sensor surface that supply local discrete data.
The passive-pixel sensor (PPS) is a type of photodiode array. It was the precursor to the active-pixel sensor (APS). [20] A passive-pixel sensor consists of passive pixels which are read out without amplification, with each pixel consisting of a photodiode and a MOSFET switch. [24]