while i was reading about dvi-i cables i have seen that it can support both analog video signal and digital video signals.can u explain me about the difference between analog and digital video signals . thanks you
Analog signals - https://en.wikipedia.org/wiki/Vga
Digital signals are just that - the picture to be displayed is sent as a set of data bits through LVDS and the monitor or screen at the other end decodes the information and displays the image.
One thing i am not clear.As the image are present in binary values in hard disk , then why the video card want to convert brightness to analog and analog to brightness(for analog monitor) rather than converting digital values to analog .sorry if my thought is wrong.Thank you in advance
No the data isn't stored on the hard disk. It is written by the CPU to the video card (greatly simplifying things) which then does the work to convert it to either an analogue signal or a digital signal.
The video card then converts this data to a red / green / blue voltage with appropriate signal timings for the VGA or a digitally encoded value for HDMI / DVI.
Again - greatly simplifying things but may make it a bit easier for you to understand.
Why do you care?, it makes no difference - VGA is just as good as DVI or HDMI - in fact it 'could' even be slightly better (as 'could' either of the other two), but essentially they are the same.
one last doubt.every one says that video card do his work and then its feed to computer and sound card converts the digital things to analog.but explicitly i did not see that on my cpu.is it embedded in pc.if so where it will be.thank you