Will a DVI connection improve the display on an LCD with only a VGA input?

B

Bob Knowlden

A DVI-to-VGA puts the analog signal from a DVI-I connector onto the proper
VGA pin. It's a passive device.

I doubt that there is any meaningful difference between the analog signal
present at a VGA connector on a graphic card and the analog signal on the
DVI-I port.

Don't bother.
 
S

Shenan Stanley

Joe said:
Is an LCD monitor with just a VGA input, a digital device? If it
is, will using a DVI to VGA adapter connected to a DVI graphic card
improve the sharpness of the LCD display?
Thank you for any information!

No DVI connection on the monitor - no adapters will do anything - in fact -
it is more likely to degrade the signal by some miniscule factor.

If your monitor does not have a DVI connector - connecting it to your
computer through a DVI-to-VGA converter will do you no good. Purchase a
better monitor. ;-)
 
J

Joe

Hi,

Is an LCD monitor with just a VGA input, a digital device? If it is,
will using a DVI to VGA adapter connected to a DVI graphic card
improve the sharpness of the LCD display?
Thank you for any information!

Best,

Joe
 
V

VanguardLH

Joe said:
Is an LCD monitor with just a VGA input, a digital device? If it is,
will using a DVI to VGA adapter connected to a DVI graphic card
improve the sharpness of the LCD display?
Thank you for any information!

The only reason you'd use the DVI-to-VGA adapter (at your video card;
see http://ucables.com/img/extra/DVI-TO-VGA-ANALOG-ADA-R53960-0.jpg) is
because your video card only has DVI output(s) but your LCD monitor only
has VGA input. Putting any connector in the cable between the video
card's output to the monitor's input will attenuate the signal but
perhaps by not a sufficient amount to affect quality of the signal
received by the monitor. The more connections and the longer the signal
path the more the attenuation and noise.

If your video card has both DVI and VGA outputs but your monitor only
has a VGA input then connect VGA to VGA. With only DVI available from
your video card and only VGA on your monitor, you're forced to use the
adapter. DVI was designed to be backward compatible with VGA by
providing the analog pinouts needed for a VGA connector (through an
adapter).

Schematic of DVI-to-VGA adapter:
http://www.instructables.com/files/deriv/FQ9/W4M3/F4REC0X6/FQ9W4M3F4REC0X6.MEDIUM.jpg

Only a few of the DVI's pins (the analog signals) are transferred to the
VGA pins:
http://farm1.static.flickr.com/37/91317333_12ea7764e7.jpg

You're feeding only the analog video signals from the DVI connector to
the VGA connection. You will lose out on the binary (digital) data
signals to the monitor which allows for some automatic setup at the
monitor.

Digital Visual Interface (DVI):
http://en.wikipedia.org/wiki/Digital_Visual_Interface
"As well as digital signals, the DVI connector includes pins providing
the same analog signals found on a VGA connector, allowing a VGA
monitor to be connected with a simple plug adapter. This feature was
included in order to make DVI universal, as it allows either type of
monitor (analog or digital) to be operated from the same connector."
 
B

bucky3

Is an LCD monitor with just a VGA input, a digital device? If it is,
will using a DVI to VGA adapter connected to a DVI graphic card
improve the sharpness of the LCD display?

No.

I have an LCD monitor with dual inputs (VGA and DVI). I can't tell the
difference between using VGA vs DVI cable.
 

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