Questions about computer power supplies....

I have a 200w power supply out of a desktop computer (Dell PN K0564), and I wanted to use it to power a 12v air compressor...Im completely useless with electrical...is there a way this can be done? Please help

Red + Black leads = 12v supply

Yellow + Black = 5v

It will depend on how many watts the air compressor requires for operation. If it's 200 or less you should be okay, if it's more that power supply isn't going to work.

If the air compressor is labeled with amps and not watts, 12 volts x __ amps = watts.

thanks guys., this helps a lot, but unfortunately, theres no wattage/amperage specs anywhere on it. Its meant to run off your 12v cigarette lighter in your dash. Thats usually on a 15a fuse, so the approx 16 amps the 200w power supply can make should be sufficient, correct?

maybe someone else can find the specs - my google fu is letting me down

Air Compressor

Grtechguy wrote: Red + Black leads = 12v supply Yellow + Black = 5v

Got that one backwards. Yellow is +12V, red is +5V. Black is ground. Each molex connector has 1 +12V, 1 +5V, and 2 grounds.

I use an old AT PSU for my RC car charger power supply.

The power supply in question, does it have a hard switch or does it have a soft switch. You really want one that has a real on/off switch that connects to it. If it doesn't, you're going to have to ground out one of the pins in the main connector and provide a load on the +5V rail to get good power out of the +12V rail. You don't have to do that with an old AT power supply, just with ATX and newer power supplies.

Do also note that PSUs are rated in 5V x amps + 12V x amps + 3.3V x amps. Some less scrupulous companies add ALL of the ratings together to give you the power rating of the PSU.

/edit: I did google the part number for that PSU, and it is an ATX PSU. Jump the green pin on the main connector to black and it will power up. Because of the way power supplies are designed, you likely won't get rated power out of it without a load on the other main rail, but you'll probably get enough for a small air compressor.

The power supply in question has ratings as follows :

DC Output: +5v 22A, +12v 10A, +3.3v 14A, -12v 1A, +5VFP 2A +5v and +3.3v Shall Not Exceed 135W

That should be enough.

/edited again for more info and for clarity.

/edit 3: That compressor is powered by a 550 motor. I don't see it exceeding the rating of the power supply.

WOAH! thanks Derick!!!

I'm a geek, that's what I do