SpudFiles

Ok so I have a 555 timer circuit rated at 12v dc, typical idle current 20ma, typical active current 55ma
From this I am running an 80mm computer fan rated at 12v
Does anyone out there have any idea how I would possibly use 2x pp3 battery’s totalling 18v and bring that voltage down to between 12 and 15v?
Plans for a small circuit maybe? as I am finding it difficult to find a step down transformer which will run this.
Cheers to anyone who can help.

use a voltage regulator, they're about 3 bucks at radioshack

Resistor maybe?!?

a resistor is the best way to go, and i dont think you will lose any current that matters...
why are you using the 555 in the first place? i would just use a switch and be done with it or are you adding in some extra stuff?

my idea;

----------|'|'|'+--------/ ○----
| |
| __ |
| / \ |
-----------| fan |-------------
\___/

ill assume you understand that since you know what a 555 timer is

I had it already so thought i would put it to use, I also have a curcuit producing a large spark similar to the stun guns, which i am trying to incorporate. This is so i can hit the button and i know i have 20-30 secs to move out of the way for the first shot, just extra safety and all that.

I went down to my local electronics store and asked about the regulator, they said it would not work? too much voltage running through it. He said try a step down transformer (Which i dont think they do for such small voltage) I dont think these guy's know what there on about (They look at you all wierd when the technical questions come out.

Thanks for the replies i think i have managed to sort it. I used 9v to power the circuit giving me approx 5-6v on the output through the relay and then shoved another 9v on the end of that into the fan it works a treat!!!

I shall post the picks once done it's starting to come on well (Especially for a UK spudgun, as most people are like A WHAT???)