I just bought a mini-display to HDMI converter to connect my iMac to HDTV. The connection works just fine but there's one problem that I discovered. OSX Mavericks provides no option to turn off your Mac display when using external monitor. I first thought there should be a simpler way to do that; but it turns out that there's absolutely no way OSX allows you to do that. I don't know if it's meant to be that way OR Apple's just forgetting this simple yet useful facility. I however found a way to make that happen without using any third-party app. The idea is simple. Connect your external display to your Mac and once you get the desktop to appear on the external display, simply decrease the brightness of your Mac screen to minimum; that the screen goes dark. I've no clue whether this would help save battery on the Mac; but I believe setting the brightness to minimum should be equivalent to turning the display off - because the screen does not have to render the contents on screen. If you know any other mechanism that helps achieve this; please let me know. This issue forms one of the few issues I have with the OSX system. Apple shouldn't call it 'world's most advance OS'. You've gotta let people do what they want and not be a dictator, Apple! If you want a third-party app to do this for you; there's a program called "Shades" https://www.macupdate.com/app/mac/23370/shades . I have not used it; but I found a few recommendations online. Use it at your own risk. For now, turning the display off is the best way to deal with this problem. Let's wait that OSX engineers will fix this up some day.