Chromecast is a USB device that goes onto your computer. If you have a modern television in range it will see that signal and take it as it's own for broadcasting on the really big screen. Im working on that myself. I might get it I have a BenQ 24 inch gaming monitor that does a very good job, but am beginning to run into limitations with screen space and my eyes. Working on something larger. Much larger.
Get a Google Chromecast for $35 and stick in the HDMI port of your tv. You'll be able to watch anything on your phone with your tv. (netflix, directv, etc)