Editing Vacuum tube (section)

===Cathode-ray tubes===
{{Main|Cathode-ray tube}}

The [[cathode-ray tube]] (CRT) is a vacuum tube used particularly for display purposes. Although there are still many televisions and computer monitors using cathode-ray tubes, they are rapidly being replaced by [[flat panel display]]s whose quality has greatly improved even as their prices drop. This is also true of digital [[oscilloscope]]s (based on internal computers and [[analog-to-digital converter]]s), although traditional analog scopes (dependent upon CRTs) continue to be produced, are economical, and preferred by many technicians.<ref>[https://www.electronics-notes.com/articles/test-methods/oscilloscope/analogue-oscilloscope.php Analogue Oscilloscope: cathode ray oscilloscope]''electronics-notes.com''</ref> At one time many radios used "[[magic eye tube]]s", a specialized sort of CRT used in place of a [[Galvanometer|meter movement]] to indicate signal strength or input level in a tape recorder. A modern indicator device, the [[vacuum fluorescent display]] (VFD) is also a sort of cathode-ray tube.<ref>{{Cite patent |country=US |number=5463290 |title=Power supply stabilization circuit with separate AC/DC negative feedback paths|inventor1-first=William V. |inventor1-last=Fitzgerald|pubdate=1995-10-31|assign=[[Thomson Consumer Electronics|Thomson Consumer Electronics Inc.]]}}</ref><ref name=workings>{{cite web |title=How Computer Monitors Work|date=16 June 2000 |url=http://computer.howstuffworks.com/monitor7.htm |access-date=4 October 2009}}</ref><ref>{{Cite web|url=https://www.cnet.com/news/remember-when-tvs-weighed-200-pounds-a-look-back-at-tv-trends-over-the-years/|title=Remember when TVs weighed 200 pounds? A look back at TV trends over the years|first=David|last=Katzmaier|website=CNET}}</ref>

The [[X-ray tube]] is a type of cathode-ray tube that generates X-rays when high voltage electrons hit the anode.<ref>Coolidge, {{US patent|1,203,495}}. Priority date May 9, 1913.</ref><ref>[http://www.bruker-axs.de/fileadmin/user_upload/xrfintro/sec1_3.html Diagram of continuum and characteristic lines] {{webarchive |url=https://web.archive.org/web/20080223224617/http://www.bruker-axs.de/fileadmin/user_upload/xrfintro/sec1_3.html |date=February 23, 2008 }}</ref>

[[Gyrotron]]s or vacuum masers, used to generate high-power millimeter band waves, are magnetic vacuum tubes in which a small [[relativity (physics)|relativistic]] effect, due to the high voltage, is used for bunching the electrons. Gyrotrons can generate very high powers (hundreds of kilowatts).,<ref name=Richards2010>{{cite book|last=Richards|first=Mark A.|author2=William A. Holm|year=2010|title=Principles of Modern Radar: Basic Principles|chapter-url=https://books.google.com/books?id=nD7tGAAACAAJ&q=principles+of+modern+radar:+basic+principles|chapter=Power Sources and Amplifiers|publisher=SciTech Pub.|pages=360|isbn=978-1891121524}}</ref><ref>{{Cite book|last1=Blank|first1=M.|last2=Borchard|first2=P.|last3=Cauffman|first3=S.|last4=Felch|first4=K.|last5=Rosay|first5=M.|last6=Tometich|first6=L.|title=2013 Abstracts IEEE International Conference on Plasma Science (ICOPS) |chapter=Experimental demonstration of a 527 GHZ gyrotron for dynamic nuclear polarization |date=2013|pages=1|doi=10.1109/PLASMA.2013.6635226|isbn=978-1-4673-5171-3|s2cid=31007942}}</ref> 
[[Free-electron laser]]s, used to generate high-power coherent light and even [[X-ray]]s, are highly relativistic vacuum tubes driven by high-energy particle accelerators. Thus, these are sorts of cathode-ray tubes.<ref>{{Cite journal|last1=Margaritondo|first1=G.|last2=Rebernik Ribic|first2=P.|date=2011-03-01|title=A simplified description of X-ray free-electron lasers|journal=Journal of Synchrotron Radiation|language=en|volume=18|issue=2|pages=101–108|doi=10.1107/S090904951004896X|pmid=21335894|pmc=3042323|issn=0909-0495|doi-access=free|bibcode=2011JSynR..18..101M }}</ref><ref name="huang">{{Cite journal | last1 = Huang | first1 = Z. | last2 = Kim | first2 = K. J. | doi = 10.1103/PhysRevSTAB.10.034801 | title = Review of x-ray free-electron laser theory | journal = Physical Review Special Topics: Accelerators and Beams | volume = 10 | issue = 3 | pages = 034801 | year = 2007 |bibcode = 2007PhRvS..10c4801H | url = https://digital.library.unt.edu/ark:/67531/metadc887443/m2/1/high_res_d/896722.pdf | doi-access = free }}</ref>