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 (fō′tō-to͞ob′, -tyo͞ob′)
An electron tube with a photosensitive cathode.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Electronics) a type of photocell in which radiation falling on a photocathode causes electrons to flow to an anode and thus produce an electric current
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈfoʊ təˌtub, -ˌtyub)

an electron tube with a photosensitive cathode, used like a photocell.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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References in periodicals archive ?
Production of ROS by RCI involves the action of ultraviolet (UV) light (produced by a UV phototube) interacting with metal catalysts.
Sani, "Phototube sensor for monitoring the quality of current collection on overhead electric railways," Proc.
The energy deposited in a given module was obtained from the geometric mean of the two phototube signals, and the horizontal position of the energy deposit was determined from the attenuation length of the scintillator and the ratio of the phototube signals.
A separate program, assuming equal phototube efficiencies, was developed for evaluating the effects of varying different input and model parameters.
Each cone, part of an experiment called CYGNUS, contains a plastic sheet that scintillates when a particle strikes it; a phototube at the top of each cone senses the faint burst of light.
The "aperature" is an adjustable opening allowing a variation in the area of surface examined and the amount of light reaching the phototube. The analyzer, a second prism in a graduated circle, can be rotated until a minimum intensity is achieved, as indicated by the photometer.