CGA/EGA to VGA on a budget

Описание: With the use of nothing more than a XOR gate and a diode clamp, you can turn a cheap and otherwise useless converter into something useful. This setup is adequate to view and test the output from CGA and EGA devices, where in some cases switching to a VGA card may not be desirable or possible. Of course, we also brush upon the history of these video cards as well as a few simpler circuits you can make if you just want a picture, but don't care about the image quality very much.

The total cost should be quite low, even if you have to buy the components other than the converter, especially as you only really need the CGA part of it. It'll certainly be cheaper than finding a real CGA or EGA screen in most cases. Of course you won't have access to all modes or all colors with this device, plus the colors you do get will be off, but you can get a surprising amount of things to work.

If you really want me to, I might be willing to have another go at the monochrome cards and also may well be tempted to build a better CGA/EGA adapter.

If you want more information on the principles employed in this circuit, you might have luck searching for 'diode voltage clamp', 'XOR gate', 'transistor XOR gate' and 'r2r ladder'.

Places where I can be found outside of YouTube;
  / discord  
http://forum.dxzeff.com/
  / high_treason   (Not really used any more)
   / hightreasonlp