Super USB Charger, and 12V Power Supply

This is super super simple power supply that will give you a high current 5v supply you can charge a zillion devices at once with, and a decent 12v power supply. No soldering required.

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Step 1: Mount Screw Terminal Strip, Cut Wires, Separate Wires, Trim Wires, Strip Wires, Attach to Terminal.

First, you need a PC Power Supply (aka, ATX Power Supply). And order some of these, they are an AWESOME value: They cost about $1.04 a piece (5 for $5, like Arby's sandwhiches used to be). My Dad gave me 4, and I used 3 of them in a few weeks they are so handy. So if you can afford it, go ahead and buy a dozen :)

Attach the terminal block someplace on the power supply. I like the cord hanging down, and the terminal strip facing me. You could glue it on, use velcro, or use self drilling screws to attach it, whatever, doesn't really matter. (If you do use self drilling screws make sure you aren't drilling into the pcb inside the power supply).

Cut ALL the connectors off of the end of the wires. Cut it close to the connectors, trust me, you'll probably NEVER use those connectors.

Separate all the wires and group them by color. All you care about are the Green, Black, Orange, Red Yellow. Group the Green wire with the Black wires.

Trim the wires to the same length as the rest of the ones of the same color.

Strip the ends of the wires. Twist the same colors together (Green goes with Black). And clamp them down in the screw terminals. The Power Supply turns on when the Green wire is attached to the ground (black) wires.

Viola! You are done! It's that easy.

To touch it up, you can cut the other wires short, and tape the ends off. Or use zip-ties to keep it short.

Black is ground. Yellow is 12V, Red is 5V, Orange is 3.3V. You can easily cut a usb cable and attach it to the 5v supply to charge devices. I used the 12V supply to hookup a car audio amp and speakers with a sub-woofer to my computer...

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    5 Discussions


    3 years ago

    "You can easily cut a usb cable and attach it to the 5v supply to charge devices"

    I think you should show how since it's the name of your Instructable.

    Otherwise you should change the name to "How to wire a PC Power Supply to a terminal strip." ;-)

    BTW some PC power supplies won't switch on unless there is a load on the 5v bus.

    4 replies

    Reply 3 years ago

    Hey Brian,

    Thanks for the comments. Most devices now days will charge if you give them 5v without anything special. Yes, some require voltage dividers, and some require the D+ and D- lines to be tied together, but not all. If you just cut a usb cable, get the red and black wires and attach to 5v+ and ground, it may work for your devices. If not, you'll need to find out what your device needs.

    There are also quite a few USB charging cables floating around that only have a + and - wire.

    I have heard several people say things about PC power supplies, like "You have to have a load on it, or it is bad." But I haven't heard any first hand accounts yet. Can you tell me more about the power supply not switching on unless there is a load on the 5v side? I've never heard of it before.


    Reply 3 years ago

    The Wikipedia page on ATX power supplies is a good read, I like the history section. They quote from the ATX specs including the "ATX12V Power Supply Design Guide" which can be found on (Google for it)

    The wiki page mentions the load requirement but the current spec does not! So I am guessing it depends on how old the supply you are using is! A newish one will probably be fine with no load. Some older supplies actually have the load requirement printed on the sticker on the case.

    So... if you pull the supply from a old PC, and it does not switch on, it could be just fine! If it works with no load, and the voltages are in spec, be happy and go with it. Otherwise you will need to load the supply for it to work. It's very important to understand this if the PC is broken and you bench test the supply. If the supply does not start up on the bench it could still be fine.

    Side note: the 5VSB (SB="Standby") power line is always switch on and
    is suppoed to provide up to 2 amps. You could use that for charging a
    USB device even when the power supply is switched "off".

    BTW I have many recycled phone chargers and small 5v supplies, when I need to charge a phone I normally use a phone charger. ;-)


    Reply 3 years ago

    Interesting, thanks for the kind response! I will read that sometime.


    Reply 3 years ago

    If you are scavenging parts from a PC, you could take the USB connectors from the motherboard and wire them up. Then you could have (for instance) power on 4 USB connectors and you don't have to cut any USB cables in half.

    I hate those charge-only cables!! They are so sneaky, pretending to be USB cables when they are not. When I need a data cable and plug one of those in accidentally it is very irritating! Cutting those ones in half to reuse them is a good idea.