18v dropped to 12v?
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.
Discussions
11 years ago
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.
11 years ago
Get a free sample 7805 from fairchild. I got a few of them. They will give you lots of stuff for free
Reply 11 years ago
7805 gives 5 volts, not 12
Reply 11 years ago
oops, 7812. Haven't slept much recently....
11 years ago
. How much current will the load be pulling?
Reply 11 years ago
about 500ma for a ccfl
11 years ago
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
Reply 11 years ago
actually, 3 ways: or a zener diode!!
11 years ago
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!