bench power supply from pc power supply

@carlso1940

Welcome to the Forum!

The -12V is a negative 12 volts referenced to ground.  It is used on the PC motherboard it might be (or at one time was) connected to.  You can probably ignore this wire and get rid of it if you're never going to use the -12V.  I did not use that on my power supply and at the moment can't envision ever having a need for it.

Posted by: @carlso1940

Also, as a newbie, I do not understand -12v wire. What is it used for?

The -12-volt output is there to power the RS-232 (serial) ports, they required both positive and negative 12-volts. It is a very low current output, probably just a few milliamperes.

It's been decades since they made computers with serial ports, as Steve (Code Cage) has said you can essentially ignore it.

😎

Bill

Thanks for the replies fellows. But what is the brown wire, that I mentioned, used for?

carl

@carlso1940

The brown wire is a "sense" wire, it needs to be connected to one of the 3.3-volt outputs, which pin 13 is (like all of the other orange wires).

It is used by the power supply to "sense" that the 3.3-volt output is at the proper voltage level. When you convert your power supply you'll need to keep it connected to one of the orange wires.

😎

Bill

Thanks Bill ! That brown wire really had me bugged.

I think I will snip the blue wire and like I did inside the box I will put a dab of liquid tape on end of wire.

Now one more question, you can tell I am an 80 year old newbie. Where can I locate the parts you used  in the video?

Carl