12V to LCD

Posted on 2005-04-15
Last Modified: 2010-04-30
Hi experts,

I got a 7" LCD monitor

it has a red wire and a black wire, and takes 12V.

I would like to power it using a cable coming from my computer's PSU.  Preferably a floppy cable.  I was wondering if anyone knows which color is which.  Is yellow 12V?  is red 12V?  are the blacks always GND?

Question by:dbrownell83
    LVL 6

    Accepted Solution

    Hi Dan,

    Yellow = 12V
    Black = Ground
    Red = 5V

    Besides that, I'm not sure if the power coming out of that is compatible or not.  Somebody else here may give their 2 cents about it.

    Good Luck!  :)
    LVL 13

    Assisted Solution


    Yes, the power from a drive power cable should be fine if you have the capacity to spare.  Black is ground, yellow is +12 volts.  If 12 volts is what you need, connect the yellow wire to the red wire of the display, black to black.  From what you have said it should work fine as long as the power supply has adequate capacity (the display is likely to draw about 1 to 2 amps, a bit more than a typical drive).
    LVL 13

    Assisted Solution

    Dan, on average a 17" LCD Monitor will use 3 to 4 amps, but the more important infomation is that it will consume about 60 Watts, whereas a Hard Drive consums 25 to 30 Watts.  Watts is how your Power Supply is rated.

    As I have stated in similar questions, to know how much Wattage you need in a power suppy, here is a rough guide, and allow at least 30 watts over:

    AMD Athlon 64 - 90 to 110w
    AMD Thunderbird - 50 to 60w
    AMD Athlon XP - 50 to 80w
    AMD Duron - 40 to 60w
    Intel P4 - 60 to 100w
    Intel PIII - 25 to 40w
    Intel Celeron - 30 to 60w
    Motherboard - 18 to 28w
    Opical Drive -each - 30w
    Hard Drive-each - 25w
    Memory Stick (Each) - 7 to 12w
    Non Powered USB/Firewire (Each) - 5 to 10w
    AGP - 10 to 15
    PCI Video Card - 15w
    PCI Card (Each) - 5w
    Internal Powered Sound Cards (SB Audigy 2 ZS) 12v @ 25w
    Fan (Each) - 3w
    Keyboard & Mouse - 6w

    Personally, I wouldn't hook up an LCD Monitor that way, but as I haven't ever tried it...I wouldn't know.  Most all LCD monitors have 12VDC that will protect it against a power surge, even though your PS in your system is regulated, there is nothing to stop a power surge if it goes bad.
    LVL 1

    Author Comment

    thanks all

    lennon, it's 7", not 17", so i think it'll be ok.  but thanks for the wattage info
    LVL 13

    Expert Comment


    That's why I estimated 1 to 2 amps, which is 12 to 24 watts.  And even that might be high for a seven-inch monitor.
    LVL 3

    Expert Comment

    If that LCD was expensive you may want to consider a breaker type system if there is a power surge that LCD will get the full blast from the PSU and it could fry without one.
    LVL 1

    Author Comment

    will a fuse on the positive end work?

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