If you want to convert Apple TV 3 from AC to DC... There are a total of 8 pins on the connector from the power supply. 3 are positive, 3 negative and two leave not connected. I think the unused (at least one) pin is some kind of a temperature sensor - found that out by trial and error, if you ground that pin, Apple TV shows a message about temperature being too high and turns off. So if you are looking from the top and the HDMI connector is towards you and power supply on the right then from left to right Pins 1,2 - unused / don't connect Pins 3,4,5 - ground / negative (connect together) Pins 6,7,8 - positive (connect together) I haven't used the ATV for too long of a time on DC yet, just tried it out seems to work fine. Used a "DC/DC Converter Regulator 12V Step DOWN to 3.3V 10W 3A" converter purchased from eBay. So now Apple TV 3 working from 12V DC Now to get this into the car.