Sync on Green is a standard used for SCART input, but I've never come across a SCART TV that demands this in preference to full RGBS.
SoG is different to component (YPbPr) in that the green "chroma" is still present on the G line (TV must know how to separate it out). With component, the "Y" (green wire) carries just luma (brightness) & sync, no green. The green is not actually present at all, and green is determined by the TV using simple calculus/algebra as it already knows blue (-luma) and red (-luma) & luma.
I'd be very interested to see if someone can work out how to build a simple DIY VGA/DVI-component conversion circuit. My electronics skills aren't good enough (yet) to design such a circuit, but I could build one. There would be an awful lot of retrogaming people interested in building it.
I've also been looking at how to get component out of a PC *without* needing a converter. Some video cards support component out, but it is designed for HDTVs and video projectors that can display VGA/~31khz modes normally output by PCs like 480p, 720p and 1080p. The reason for providing this support is that these HDTVs and projectors were used a lot in business (presentations etc) and home theatre applications, but this is less common now. For us, a problem arises because SDTVs (which we prefer for retrogaming) that accept component inputs cannot display these modes.
Another problem is that it is difficult to work out just which video cards support component out in the first place. Mostly it seems to be older cards, I have no idea about newer cards. There are some NVIDIA cards that support component, but a lot more ATI/AMD cards seem to. In particular, cards with VIVO support seem to be component-capable. For example, AFAIK these old ATI cards support component out:
ATI RADEON 9800 Series
ATI RADEON 9700 Series
ATI RADEON 9600 Series
ATI RADEON 9500 Series
ATI RADEON 8500 Series
ATI RADEON 8500LE Series
ATI ALL-IN-WONDER RADEON 9800 Series
ATI ALL-IN-WONDER RADEON 9700 Series
ATI ALL-IN-WONDER RADEON 9600 Series
ATI ALL-IN-WONDER RADEON 8500
ATI ALL-IN-WONDER RADEON 8500DV
I'd be very interested to know what modern video cards (if any) support component out, but information is very scarce.
Who cares if you can't produce an image on component SDTV? Well, you
can. If your card is capable of outputting component video you are already halfway there, you just need to use another application like Powerstrip, CRT_emudriver or soft15khz to generate the 15khz modes. I've done this before with Powerstrip (long time ago) & a Radeon 9600 (iirc), but I see no clear reason why CRTEMU and soft15khz would not work like this as well. Note that these apps don't actually modify the video signal at all, they just generate modes for your card to output. Your video card does all the signal conversion for you already, if able to and configured properly.
Component video output from a compatible card will be available on the RGB signal outputs, you just need to add in ground and hack your VGA/DVI output to 3 RCA female connectors (or RCA/component cables with these male connectors on the other end). You can buy cheap, passive adapters on ebay etc for about $3. Or you can just build your own (AFAICT, all you'd need to patch through is RGB, ground. Sync is already on green). You might like to keep wires for VGA pins 11, 12 & 15 available (as these are used for monitor EDID info, which may (or may not) be needed by your video card).
https://www.ebay.com/itm/3-RCA-RGB-Video-Maschio-a-HD-15-Pin-VGA-Component-Video-Jack-Adattatore-Nero/282709683678?hash=item41d2cf6dde:g:nXoAAOSwWLBZ8rb~Why not just buy an overpriced VGA-component converter? Well, if you like, I'm a cheapskate and don't understand why you have to buy new expensive stuff to play old games (which is the default advice I keep on hearing on these forums) when there are cheaper, possibly better options. Building it is probably easier. Plus it can be hard and expensive for me to get specialised electronic stuff where I am (rural Thailand). Out of the last 3 shipments of electronic stuff from overseas, customs intercepted 2 of them, charged me more in tax/bribes and caused delays/concerns from my suppliers. It is a PITA. However, this VGA-component converter does look attractive and is getting close to the right price range:
https://www.monoprice.com/product?p_id=8668ATM, I don't even have a component input TV to test my theories on, but I do have a bunch of old video cards. I was stimulated to look into this recently by another poster who is from Columbia, who faces much worse problems than I do with getting stuff like VGA-component converters from overseas.
PS -
you don't I don't think that you need a voltage divider on the 5v sync,
but maybe it won't hurt. I've done heaps of SCART cables without needing to pull sync voltage down, had good results, and when I've tried using voltage dividers on sync it didn't help/caused problems so I removed it. Maybe I missed something.EDIT - italics on the PS, last bit
PPS - If doing a voltage divider on sync, don't forget that video signals are normally 75 ohm terminated at the TV/monitor.