damper vs vacuum tube

damper

noun
  • A device that decreases the oscillations of a system. 

  • A contrivance (sordine), as in a pianoforte, to deaden vibrations; or, as in other pieces of mechanism, to check some action at a particular time. 

  • A shock absorber. 

  • A valve or movable plate in the flue or other part of a stove, furnace, etc., used to check or regulate the draught of air. 

  • Bread made from a basic recipe of flour, water, milk, and salt, but without yeast. 

  • Something that kills the mood. 

vacuum tube

noun
  • A type of electron tube that controls electron current through vacuum between electrodes within a sealed container, usually of glass or metal and often designed to be easily installed in and removed from the equipment in which it is used. 

How often have the words damper and vacuum tube occurred in a corpus of books? (source: Google Ngram Viewer )