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[pen-tohd] /ˈpɛn toʊd/
noun, Electronics.
a vacuum tube having five electrodes, usually a plate, three grids, and a cathode, within the same envelope.
Origin of pentode
1915-20; pent- + -ode2 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for pentode
Historical Examples
  • Remember how he went to all the trouble of building a pentode vacuum tube for a job that could have been done by transistors.

    Anything You Can Do Gordon Randall Garrett
British Dictionary definitions for pentode


an electronic valve having five electrodes: a cathode, anode, and three grids
(modifier) (of a transistor) having three terminals at the base or gate
Word Origin
C20: from penta- + Greek hodos way
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
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pentode in Science
Any electron tube with the basic structure and functionality of a triode, but including two extra electrodes, a screen and a suppressor grid. The screen helps the tube respond well at high frequencies (as in a tetrode), while a negatively charged suppressor grid adjacent to the plate prevents secondary emission of electrons from the plate, increasing the efficiency of the tube. See more at suppressor.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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