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18v dropped to 12v? Answered

I want to limit two 9V battieries, in serial to 12v. I want to run a cold cathode off em, if the strain is too much, I'll join two parralell sets of two 9v batteries in the circuit. Anyway, how do I do it? I can't find any 12V regulators at all, and I don't know what sort of resistor I'd need, is there one that would limit it to 12V, with the standard 9V battery ampage? How could I archive this? Thanks.

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Josho (author)2008-08-01

Thanks everyone. I was searching eBay for "12v Regulator" and couldn't find anything, not even at Maplin (UK electronics store) they sell regulators, but after a search on their site, couldn't find any.

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LinuxH4x0r (author)2008-08-01

Get a free sample 7805 from fairchild. I got a few of them. They will give you lots of stuff for free

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tech-king (author)LinuxH4x0r2008-08-01

7805 gives 5 volts, not 12

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LinuxH4x0r (author)tech-king2008-08-01

oops, 7812. Haven't slept much recently....

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NachoMahma (author)2008-07-31

. How much current will the load be pulling?

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tech-king (author)NachoMahma2008-08-01
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guyfrom7up (author)2008-07-31

well, there's 2 ways of doing this: hook up a 7812 chip or use a voltage divider you need to know how much current you need for the latter

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tech-king (author)guyfrom7up2008-08-01

actually, 3 ways: or a zener diode!!

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Sandisk1duo (author)2008-07-31

get a voltage regulator radioshack catalog number: 276-1771 it's like $1.60 a little expensive, considering i get all my tech stuff for free! your local store should have it!

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