how to create a cheap ac/dc converter

ruthless

ruthless

Rift Surfer
ac/dc converters are really expensive, and today i will show all of you monetarily challenged people how to make one cheap, maybe even free!

step one: buy or snatch a pc power supply from a computer. stealins wrong, mmkay? also, make sure its an atx power supply. non-atx power supplies have a different wiring setup. plus they have low amperage, which could damage your 12vdc electronics.

step 2: splice the green wire with any black wire. this will allow the power supply to come on without being connected to a pc. i suggest connecting it to a toggle switch.

step 3: the yellow wires are 12v positive and the black wires are grounds. there are also 5v and 3.3v rails you can use.

congratulations, you now have a ac/dc converter, and as an added bonus, the power supply is clean enough to use in scientific testing.

i suggest getting a rosewill psu from newegg.com prices start at 20 bucks.

and always remember to get a psu that is rated for at least 100watts over what you need. also keep in mind that a 12v power supply puts out 12 watts of power for every 1 amp @4 ohms.

good luck!
 
Hi Ruthless, I don't get the 4 ohms?
Sounds like a loudspeaker impedance you are referring to?
R=V/I
so, for example: 12 volts divided by 1 amp would give a purely resistive load of 12 ohms.
12 volts with a current drain of 2 amps= 6 ohms... and so on.

Great idea though- PC supplies are usually very good, although some kick out crap and destroy radio reception on AM in particular. :)
Dave
 
yes, i was referreing to loudspeaker resistance. ive never seen an atx psu kick out crap. hope it never does.

sorry for the dumb question, but what does r=v/i mean? im interested. for example, 12 volts with a current drain of 100 amps would have a resistive load of?
 
hat does r=v/i mean? im
Click to expand...

Just ohms law. R= Resistance, I=Current (amps) and V=Voltage (Emf)

Q answer -12 divided by 100= 0.12 ohms! VERY LOW!

ah the ol 555 timers! Great fun!, very reliable beasts too!
Dave.
 
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