I have some LED stripes to illuminate my workspace. Since I have nothing else at hand, I connected it to the 12V rail of my PSU in my computer. This works very well when the computer is turned on, but I would like to be able to use the lights also when the computer is not running.

  • \$\begingroup\$ Why not just acquire a separate power supply? \$\endgroup\$
    – Andy aka
    Jan 14, 2023 at 15:54
  • \$\begingroup\$ There is powered off, and there is disconnected. Assuming your ATX PS still connected to mains and computer, there's 5 V stand by - typically no more than 10 W, with the computer consuming an unknown amount. Assuming your workspace to feature a monitor, it may be more useful to use that for illumination. And even a small EE challenge. \$\endgroup\$
    – greybeard
    Jan 14, 2023 at 15:59

1 Answer 1


That would mean the power supply is turned on, because you don't have 12V at standby. But if your LED lights don't take more than 5 to 10W, you could use the 5V standby output by using a boost converter from 5V to 9-12V. Your power supply should be capable of providing more power (in watts) than what your LED light needs.

Another way of doing this WITHOUT a boost converter is to rewire or re-arrange the LEDs on your strip so that they're in parallel instead of being in series (typically there are 3 LEDs in series with 1 or 2 resistors on 12V strips), so that the strip can run at 3-5V, though this would be less efficient, but would get the job done.

If you don't know the details or need more info on how to do that, let me know in the comments below this answer, and I will add the necessary details here.


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