I'm trying to run an old hard drive off of batteries. It needs 5 volts and 12 volts but if I understand correctly it must be ac current. I'm not very proficient with electronics and could really use some help. Keep that in mind though. Lots of technical jargon will only confuse me more. I understand some. I know how to use resistors, wire LEDs, and a few other simple things. I checked the forum before posting and couldn't find anything on it(there were posts about converting 5v dc to 230v ac but I don't think that is what I need). Any help would be much appreciated. Also, any components I need must be purchasable at radio shack.

 

Most hard drives operate off of +5VDC and +12VDC, not AC.

 

The typical power supply for a computer takes AC on the "input" and outputs multiple "DC" voltages (12,5,3.3 I believe(..NOT AC

 

I have run hard drives powered from a general purpose power supply, not a PC supply, that supplied +5 and +12 DC, and it worked fine.

Some drives draw a heavy burst of current when their motors first start, so you do need to provide at least as many amps as the drive specification asks for.

 

I'd be curious about this too.
Could you reverse an ac to dc transformer, dc to ac, and if it worked, would you loose 1/2 the power?
My thought goes where I wired a step down three phase transformer 480v high side/240v low side, 75kva in reverse to have 480v and the kva rating according to calculations was reduced to 37.5.
No positive proof though on the kva but I do have 480v using 240v.

 

It doesn't work that way. You are describing an inverter. If this borderline hijack continues I'll split it off.