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12 volt source

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  • 12 volt source

    i have a spare 240v computer power supply, is it possible to get a 12 volt source from it to run a 12v spot/fog light for the workshop? any electronic minded out there to advise me please?


  • #2
    Look on the can or box should have a tag with in put and output. Mine is an 115volt/12amp 230volt/6amp input with the standard outputs of +5volt +12volt +3.3volt -5volt -12 volt +5 volt SB I belive that is standard for most ATX power supplies if not all computers. Wattage of the supply would control how much of a light size you could use. Check the back off the box to see if there is a small slide switch to change from 230 240/ to 115 120 volt. Do so while the unit is unplugged from the mains if you are in the U.S.
    Been there, probably broke it, doing that!
    I am not a lawyer, and never played one on TV!
    All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or the suggested uses, Wear safety glasses, closed course, professionals only


    • #3
      thanks for the reply, the power pack is pretty new and works fine in a pc but doesnt seem to power up also the fan isnt switching on. there isnt a 110v switch, just 240v as im in the uk, and yes you seem to be describing the unit pretty well with the amp/voltage settings, my lad seems to think that the power pack requires a return voltage to switch the unit up, do you have any info on this please?

      kind regards,,,,bill


      • #4
        Connect the green wire to a black wire to switch it on (on the motherboard connector). Most supplies also require around .5 amp of load on the 5vdc output to run.
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        • #5
          thanks Evan, im not very good with electrical terminology, ive located and bridged the green and black wires but the 5vdc is not recognizable to me sorry,,were is it?



          • #6
            5vdc will be any of the red wires. Just connect a 6 volt tailight bulb or similar between the red and black on one of the long harnesses.
            Free software for calculating bolt circles and similar: Click Here


            • #7
              thanks Evan, i dont like to mess with power supplies as i havent got a clue with electronics, but seen as i have a good source for a 12v supply its a shame for it to stood if it could be of use, the reason why im changing to a 12v light supply is today i gave myself the fright of a lifetime, some lathe coolant must of hit the 240v lightbulb and it exploded! so im experimenting with low voltage lighting that doesnt mind getting wet, i bought a pair of 12v car fog lamps for a few quid, if this doesnt work ill buy the proper low voltage lighting. thanks for the replies......bill


              • #8
                If those fog lights have H3 halogen bulbs, they draw almost 4.6 Amps each. That's way too much for most PC power supplies. You might want to go to a building center and look for the low voltage under counter bulbs. They're usually 20W halogen and will draw about 1.7A. While you're there, you may want to just look at the power supplies and fixtures too.


                • #9
                  Low voltage lighting....

                  As CCWKen said, you might want to consider the under-counter lighting systems. Called Class 2 electrical systems, they are supplied by a transformer (isolated), low voltage and limited to 100 VA, I believe...
                  Some of the little 12 V lamps might get hot when running & maybe shatter if doused with coolant, but electricly it won't kill you....
                  I use one on my Rockwell mill. It works OK. It lives in a flex. gooseneck lamp.


                  • #10
                    Or you could try a low energy light bulb in your old fixture. These bulbs do not run hot, although they do become warm. Maplin have them and they are probably available for less elsewhere.


                    I haven't tried this by the way. I use low energy bulbs at home, but have never tried splashing them with coolant, or anything else.



                    • #11
                      try this

                      i built one to power a battery charger for model aircraft ni-cads, all i did was to put a car headlight bulb in the 5v circuit to trick the supply into thinking it was powering the motherboard. it then fires up on 12v and gives up to 3 amps.

                      e-mail me off line and i can send you the article to do it my way.


                      • #12
                        e-mail me at [email protected]


                        • #13
                          thanks guys, i decided to buy a proper unit to power the 12v lights and they work fine, the output is 6amps 75watts

                          luckily enough this unit ended this morning on ebay and the guy lived right near me. i placed a bid and won it! all the lights are up and running now, thanks.

                          Last edited by billyboy; 05-20-2006, 09:08 PM.