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Measurements compared to CRT???

Discussion in 'LCD & LED LCD TVs' started by CLH, Nov 16, 2004.

  1. CLH

    CLH
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    I am replacing my Panasonic PD30 which was a 36" screen with a diagonal of 86cm??? (visible screen).

    I'm considering the Sharp 32" which is 700 mm x 395 mm.

    As I'm without a ruler how will that compare to the PD30?
     
  2. richjthorpe

    richjthorpe
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    The Sharp 32" would give you a visible screen of 80.37 cm (Working on Pythagoras theory: a squared = b squared + c squared). 5.5 cm difference.
     
  3. LV426

    LV426
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    The Sharp 32 inch will give you a diagonal of 32 inches, all usable. For flat panels, the quoted measure is all usable. For CRTs this isn't true; the quoted measure (in inches, usually) is the external dimension of the tube - not all usable. The cmV is the usable value. In your case, 86 cm = 33.85 inches.
     
  4. woody67

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    I can't remember where, but I recently saw some adverts for small LCD TV's (under 20") and the blurb went something like .... ' 20" LCD screen (19.5" visible) '.
    I thought at the time, Oh no here we go again!
     
  5. djsat2

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    I thought that CRT measruements tended to include some of the outside casing in the measurement, so 32" would be from one corner of the case to the opposite diagonal corner. With LCDs the quoted size is the size of the actual panel used. Ive seen some 15" TFT PC monitors quoted as having the same visible screen size as a 17" CRT monitor!?!
     
  6. LV426

    LV426
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    More or less right, djsat2.

    CRT diagonals are usually quoted in inches as the external dimensions of the tube (not actually the casing). The glass towards the front of the tube is very thick (around an inch, depending on the tube size) so, roughly, a tube with an exernal diagonal of (say) 32 inch) will have a usable face of about 30 inch.

    Flat panels, on the other hand, typically have their diagonals quoted as the exact usable screen size.

    The visible (usable) diagonal of TVs is usually quoted as a metric value followed by V (eg 86cmV). This value is the one to use, to compare image size. For a flat panel, if a cmV valuie isn't quoted, then simply take the nominal size (eg 30 inch) and multiply by 2.54 to get a cm value.
     
  7. CLH

    CLH
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    So would I be right in saying if I WAS happy with the size of my 36" Panasonic CRT then a 32" LCD would only be a fraction smaller in reality???
     
  8. woody67

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    If you consider about 2' to be a fraction, then yes! :p
     
  9. LV426

    LV426
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    By my reckoning (see above), you'd be dropping from 33.85 inch diagonal to 32 inch diagonal. So - 1.85 inch less diagonal which (can't be bothered to work it out exactly) means about 1.5 inch less wide and about 1 inch less tall.
     
  10. CLH

    CLH
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    Given that the 28" I currently have (since my PD30 is awol) is about 24 diagonal I think I can probably live with that!
     
  11. Moe

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    There is an Industry standard for measurement of CRT screens.This allows only for the visible screen diagonal to be quoted in cmV...not inches.The exception is old 4:3 non FST (Flatter,Squarer Tubes) CRT's (in reality only basic 14"/34cmV sets now)which can be quoted in overall tube diagonal in inches,plus the visible screen size in cmV.The conversion from Imperial to Metric is therefore unequal.Manufacturers usually overcome confusion by judicious use of model numbers.

    This standard,however,is often not used by retailers who still describe CRT TV's as 28"/32" etc.

    Confused?
     
  12. LV426

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    Maybe so. But model numbers still typically include the tube size (inch measurement) - perhaps not quoted as a measure, but still implied by the ABC32XY style (= 32 inch tube).
     
  13. Moe

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    That's what I meant by "judicious use of model numbers"
     

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