[ foh-toh-tran-zis-ter ]

  1. a transistor that amplifies current induced by photoconductivity.

Origin of phototransistor

First recorded in 1945–50; photo- + transistor

Words Nearby phototransistor Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

British Dictionary definitions for phototransistor


/ (ˌfəʊtəʊtrænˈzɪstə) /

  1. a junction transistor, whose base signal is generated by illumination of the base. The emitter current, and hence collector current, increases with the intensity of the light

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for phototransistor


[ fō′tō-trăn-zĭstər ]

  1. A transistor that regulates current or switches it on and off based on the intensity of the light it is exposed to rather than an external electric signal. Phototransistors are used in many electric-eye applications, including digital cameras, in which millions of tiny phototransistors map an image into an array of electrical signals. See also photoelectric effect.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.