Another question about CRT

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Badar

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Well i am not sure this is especially CRT or is the case with other displays too.
I've seen some videos in which I see some monitors that are on. But there colors doesn't seem normal and horizontal lines appear to move upwards or downwards, but in real they are quite normal.they don't have any false colors or there are not any lines travelling along y-axis either direction.
I have also seen my monitor from the hole of my EVAPORATIVE COOLER through its fan and i could even see these lines travelling along the y-axis but i think colors were normal.When i directly watched my monitor it was normal and there wasn't any unusaul behaviour.
Is there any problem with my observation or there are some reasons for this behaviour.And also does it happen only with CRT or is common in any type of display if this is a true observation.
 
Is it just because of the way a CRT works? I would imagine the guns are moving much faster than a fan or camera.
 
Learn about how a CRT draws a picture using only a single dot of moving light, before they are completely obsolete. I think a CRT is obsolete.

Learn also about "persistence of vision" which is why you don't notice the image blinking quickly.
 
It's the interaction between two moving objects (stroboscopic effect) - you don't get this with LCD or Plasma, because the image isn't scanned like a CRT.
 
Nigel Goodwin said:
It's the interaction between two moving objects (stroboscopic effect) - you don't get this with LCD or Plasma, because the image isn't scanned like a CRT.
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Then why does my mouse "arrow" look like a stroboscope on my LCD monitor?

My hand moving in front of my LCD monitor doesn't show a stroboscopic effect because the screen is just a continuous light?
 
Thanx.I think i know a little about how the image is formed on CRT screen.May i conclude from your posts that When looking through a fast moving fan, the blades of the fans hinders afterimages of 8ms. if so, it is hard for me to visualize why the lines are moving on y-axis even when there is a still image on the screen and then what happens in the case of cameras.Can you further elaborate the answer please.
 
Badar said:
Can you further elaborate the answer please.
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Look on the web about how a CRT works.
It has a single dot of light that scans the image. The dot moves for many lines horizontally to draw the image. When the dot reaches the bottom then it starts scanning from the top again.
The image flickers at the refresh rate.
 
Badar said:
if so, it is hard for me to visualize why the lines are moving on y-axis even when there is a still image on the screen and then what happens in the case of cameras.Can you further elaborate the answer please.
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It is the same effect you get when you see a spoked wheel in a TV show such as a western. The spinning wheel appears to rotate backwards or at the wrong speed as the wagon rolls across the screen. If you lay on your back under a spinning ceiling fan and blink your eyes rapidly, you'll see the same effect.
audioguru said:
Then why does my mouse "arrow" look like a stroboscope on my LCD monitor?
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Because the mouse pointer position is not updated at the same rate as the screen is. If you move the mouse back and forth sideways really rapidly you'll see 3-5 pointers at once.
 
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audioguru said:
Then why does my mouse "arrow" look like a stroboscope on my LCD monitor?
Click to expand...

Because the "arrow" isn't 'moving' it's being turned off and replaced with a new version elsewhere - this is done at a fairly slow refresh rate, which is why you can see it happening when you move the mouse.
 


Isn't there 3 dots of light?(1 for each color)
 
crt obsolete? i hope not, they finally spent 40+ years getting them in the range of "awesomeness" and now were gonna be stuck with crappy looking lcd's and expensive plasmas. Hope CRT is here to stay for awhile, even though they're hard on the eyes, they look fantastic.
 

You need to reduce your medication!

CRT is already GONE! - no respectable manufacturers make CRT sets anymore, and even the cheap crap makes are few and far between.

A good LCD or Plasma has a better picture than a CRT anyway, but Plasma is fading out now as well - too expensive, too power hungry, and too unreliable.
 
hell i think my viewsonic crt looks better than a lcd, but that's just my very humble it's almost shy opinion.
 
My LCD monitor has so many very small dots of light that I can't count how many there are per mm with a magnifying glass. You can easily see the dots or stripes on a CRT monitor.
 
audioguru said:
My LCD monitor has so many very small dots of light that I can't count how many there are per mm with a magnifying glass. You can easily see the dots or stripes on a CRT monitor.
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Depends on the resolution of the monitor, better ones have high enough resolutions so you can't see them.
 
I remember seeing convergence and purity problems on CRT monitors.
Many had an image burned in.

My bank has some monitors that are so dim and "bloomed" that they are difficult to see. Their "best before" date has expired.
 
crusty said:
hell i think my viewsonic crt looks better than a lcd, but that's just my very humble it's almost shy opinion.
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When interfacing via VGA, you need to run the LCD at it's native resolution for it to look good. If you use a resolution that doesn't match, you'll get banding and blurring effects. Your refresh rate should also be set to 60Hz and nothing else when using an LCD. The best interface to use is DVI but only newer video cards come with a DVI interface.
 

No advantage using DVI, it's EXACTLY the same as VGA, and you can use a simple cable to connect one to the other. There is a varient of DVI though which is digital, and is a varient of HDMI - but this probably isn't used on computer monitors? (no point).

Likewise, you don't have to run an LCD monitor at it's full resolution, and most look perfectly fine like that - although certainly some laptop screens look absolutely horrible at 640x480 as you install Windows.

As for having to use 60Hz? - a complete load of rubbish - use whichever looks best, and it will probably be higher than 60Hz usuually!.
 
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