So it would appear to be better to get a Hauppauge card and be done
with it.
There is a horrid little conversion cable, that takes VGA on one
end and claims to put TV on the other end. A schematic I found
for a hobby version of the same thing, uses a series of
resistors to mix the R, G, and B together, and I think
the result is monochrome (it uses the NTSC formula and mixing
percentages). It also mixes the sync signals in, and
the sync signals have to be inverted from their normal polarity,
for the scheme to work (the video card has to be programmed
somehow to do that). I don't think that method is capable of
making a color picture, because stuff like color burst and the
like would be missing.
A second kind of device is a "scan converter". These seem to
have come down in price over the years, so are a bit more
affordable than they used to be. (It is likely cheaper to
just buy a video card that has Svideo/baseband TV-out plus
the normal VGA output, but if you really want to keep your
current VGA-only video card, or you are using a laptop that
cannot be upgraded, then a scan converter will work).
http://www.aver.com/2005home/product/pc_to_tv/pc_to_tv.shtml
To give you a hint as to what the scan converter is doing,
have a glance at this patent. A scan converter is much more
complicated than the horrid conversion cable mentioned above.
http://www.freepatentsonline.com/4658293.pdf
Note that a TV set lacks the bandwidth to display text properly.
If you just want to watch movies, it'll be fine. But if the
plan is to look at text documents on the TV, you'll get a
headache in no time.
There are plenty of video cards out there, that have a TV-out
connector. The one in the following picture, has a DIN connector
in the middle of the faceplate. A conversion connector or
conversion cable is used to deliver either a composite signal
(RCA connector) or a Svideo signal (the one with the four pins,
chrominance, luminance, GND, GND). If you buy a new video card
that has TV-out, make sure the retail package includes the
necessary adapters. Having to buy adapters later can be
expensive.
http://www.newegg.com/Product/ShowImage.asp?Image=14-164-014-01.JPG
And if the TV has neither composite (RCA jack) nor the four pin
Svideo, then you'll need an RF modulator to broadcast the output
of the scan converter, to TV channel 3 or 4. That is how devices
like the Nintendo used to do it. If that is the kind of TV
you plan on using, I'd give up on the concept completely
HTH,
Paul