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Are there any uses for Cathode Ray Tubes in modern world. TVs and Monitors were first, then Oscilloscopes, I am not sure about Radar but are there any applications which will only work with CRTs or which have and edge for CRT use?

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    \$\begingroup\$ They're useful as a didactic tool for teaching about electron motion and how phosphors can be excited by electrons. They, like other vacuum tubes, are more resistant to damage by EMP than semiconductors, though I don't know if that would be any real advantage--EMPs don't happen often enough to need that. But above all else, they are good at giving things that old-fashioned look! \$\endgroup\$
    – Hearth
    Apr 29, 2017 at 21:54
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    \$\begingroup\$ What's opinion based in this question? The obsolescence status of a technology is a market condition which can be verified by statistical data. Of course the interpretation of that data can be somewhat subjective, but this can be said to most EE design decisions! Voting to reopen. \$\endgroup\$ Apr 29, 2017 at 22:00
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    \$\begingroup\$ @pipe Sorry, but there is nothing in the rules that prohibits this kind of questions. The close reason is not justified, imho, as I said in a comment above. \$\endgroup\$ Apr 29, 2017 at 22:03
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    \$\begingroup\$ I don't think it should be closed, but it isn't an especially well-written question since the answer wouldn't be very insightful. A better question would be along the lines of "what advantages do CRTs still have over more modern display technologies?" There certainly are plenty. \$\endgroup\$
    – Phil Frost
    Apr 29, 2017 at 22:19
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    \$\begingroup\$ This is precisely a question about end user usage reason for one vs the other. It would only be on topic if it were about the design of a CRT or LCD or other monitor, which it isn't. \$\endgroup\$ Apr 30, 2017 at 2:36

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The display is much smoother on an analogue oscilloscope. You have to pay a lot for a graduated digital display that can produce as perfect a sine wave as :-

sine wave

If you get something like a used Hameg, they have a simplicity about them that's great for beginners. They can also demonstrate things that require flying electrons. J. J. Thomson invented the electron using a rudimentary CRT, and this can still be replicated today in physics classes.

A tangential but beneficial use is converting old oscilloscopes to ersatz digital displays. The interweb is full of people to have connected DACs and micro controllers to them. They then make clocks, logic analysers and esoteric art. I've also seen Quake running on a few.

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  • \$\begingroup\$ The question is about the display technology, not analog oscilloscopes. \$\endgroup\$
    – pipe
    Apr 29, 2017 at 23:59
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    \$\begingroup\$ @pipe What's the big green telly like thing on the front of an analogue scope then? I guess mine's not as good an answer as your's. Oh wait... \$\endgroup\$
    – Paul Uszak
    Apr 30, 2017 at 0:26
  • \$\begingroup\$ Ironically, this is an on-topic answer to an off-topic question, because engineering tools are explicitly on topic. \$\endgroup\$ Apr 30, 2017 at 2:43
  • \$\begingroup\$ Re: "J. J. Thomson invented the electron": I rather doubt that. :-) \$\endgroup\$
    – ruakh
    Apr 30, 2017 at 4:18
  • \$\begingroup\$ As @ruakh pointed out, probably you meant discovered, instead of invented. \$\endgroup\$ Apr 30, 2017 at 11:20
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CRT displays have several advantages over more modern technologies:

  • Minimal response time, as incoming pixel data is generally beamed to the screen immediately as received, with virtually no buffering or complex processing like scaling. The phosphors also light up pretty much instantly when desired, unlike liquid crystal pixels.

  • Excellent black level (and contrast), especially when compared with older LCD technology.

  • Resolution flexibility. As CRTs don't really have a fixed raster of pixels, they can scan the display at a wide range of vertical and horizontal resolutions without having to resort to scaling.

  • Arguably color rendition.

Of course, the advantages didn't sufficiently offset the many disadvantages that CRTs have:

Higher production cost, larger environmental impact (difficult to recycle, hazardous substances, high power consumption), susceptibility to screen burn-in, sensitivity to magnetic fields, significant warm-up time, tendency to flicker, imposing mass and volume and limited maximum screen size come to mind.

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    \$\begingroup\$ "Resolution flexibility. As CRTs don't really have a fixed raster of pixels, ..." - Actually, color CRTs typically had a shadow mask to limit an electron beam to its corresponding phosphor mask. The holes in the shadow mask were effectively subpixels, fixing the resolution of the display. Any other display resolution was effectively scaled like it is in LCDs, except the scaling was done optically rather than electrically. \$\endgroup\$
    – marcelm
    Apr 30, 2017 at 10:13
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    \$\begingroup\$ I think that you've misunderstood the purpose of a shadow mask. It's not for quantization of the image into pixels. It's to cater for e-beam divergence due to multiple e-guns. Read your link again and look at the edges of the big coloured arrow. \$\endgroup\$
    – Paul Uszak
    Apr 30, 2017 at 12:28
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    \$\begingroup\$ the shadow mask sets an upper limit on the number of pixels possible, but the raster resolution was typically significantly lower than that, and in no way bound to it. using the term "optically" to describe something that manipulates electrons is brave. \$\endgroup\$ Apr 30, 2017 at 12:32
  • \$\begingroup\$ @PaulUszak Quantization into pixels may not be the purpose of the shadow mask, but it is definitely a side effect. And at display resolutions close to the limit, aliasing is a practical concern. \$\endgroup\$
    – marcelm
    Apr 30, 2017 at 13:42
  • \$\begingroup\$ @Jasen A 19" CRT with a 0.22mm horizontal dot pitch would have about 1660 dots horizontally, which is right on the edge of being able to properly display 1600x1200 without losing pixels - never mind without aliasing. Anyway, my point was that the resolution flexibility argument of (color) CRTs is a bit more complicated than it first appears ;) \$\endgroup\$
    – marcelm
    Apr 30, 2017 at 13:52

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