# Dumb basic electrical theory question

edennorman 20:26 29 Jul 05
Locked

Look I'me only a girl ok I can't be expected to know what fellahs know about electrical thingies...ok, the question (s)

I have a 12v fan that draws 0.06Amp

If I have a power supply of 12v but capable of delivering 1Amp will it overload the fan and kill it...or does the fan just take as much as it needs of the 1A available?

Ok that's it.

Thanks

eden

tasslehoff burrfoot 20:33 29 Jul 05

and have no idea what all that means!

I'm sure somebody will though :)

garrema 20:34 29 Jul 05

I recall that electric motors draw what they need so you have enough to run the fan but it won't be forced to take "1 amp"

If it were to draw more than 1 amp you would blow a fuse - at which point you would have to get a man in:-}

Completealias 20:35 29 Jul 05

Only being a girly too I think that the power supply is rated upto 1amp if you tried to put something that required 2 amps onto it then the power supply would not handle it and overload.

So as I understand it you can put anything upto 1amp on that power and it will only draw what it needs.

For example a standard 4way exstension is rated upto 13amps but you can just run a light off it if you wish.

Happy Soul 20:40 29 Jul 05

Basics.

Volts = Current X Amps. (V=IR)

Resistance = Volts / Amps. (R=V/I)

Amps = Volts / Resistance. (I=V/R)

ie. If your fan draws 0.06 amps from the 12V supply, the fan must have a resistance of 200 ohms.

If the 12V supply is capable of drawing 1amp, you could have 5 of your fans working off the same supply.

edennorman 20:40 29 Jul 05

hee hee

Funny that the best reply came from another girl :)

Thank you....I didn't think of the 13Amp mains comparison...obvious innit!

Thank you all very much.

eden

The Old Mod 20:41 29 Jul 05

Lucky you I'm a spark, the fan will draw the current it requires and no more, which is below what your power supply is rated at, so no problem.

octal 20:49 29 Jul 05

I'm an electronics engineer.

Your 12 volt fan drawing 0.06 amp on a 1 amp PSU is fine, the fan will only use 0.06 amps and no more.

If you put two fans on the PSU they would take 0.12 amp, if you put three on they will take 0.18 amp, I think you'll probably get the idea now, the more fans you add the more amps they consume.

Bagsey 21:03 29 Jul 05

<Volts = Current X Amps. (V=IR)>
Naughty.
Volts = amps x resistance. (V=IR)
Retired teacher so compelled to mark your work.:-))

Happy Soul 21:17 29 Jul 05

Bagsey. Sorry Sir.

I must check my work before posting.
I must check my work before posting.
I must check my work before posting.
I must check my work before posting........

There's an Apple in the post.

Stuartli 23:58 29 Jul 05

My two 150w light bulbs in the living room or the TV set, for example, use only what juice they require to be operational when I flick a switch.

Either you appreciate such facts or it's a bit of a windup.....:-)

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