dont hate me but i have a off topic question- id like to ask you smarty pants !

[vdubdipr]

so im buying a used underwater camera and the battery is shot. id like to just use one of my boat batteries, but i need to drop the volage from 12 volts to 9 volts. can i use a fixed pot with a certain value resistor? would i run into problems with alot more available amperage?  i just respect the hydrogen communitie's opinion so thats why im asking you! thanks buddy! 

[Yucca]

Hi vdubdipr,

You´d be best getting a voltage regulator IC like LM317 and then put your potentiometer on that to set it at 9v output.

http://english.cxem.net/power/power63.php

Yucca.

[AhuraMazda]

I think you perhaps are not an elctronics savy person. You are better off buying something like this:
ebay Item number: 110339808961.

You need to water proof it of course.

[vdubdipr]

no, im not very intellegent when it comes to that- thats why i asked thanks alot!!! i appreciate it!

[mscoffman]

Yes, a semiconductor regulator is the way to go.

Make sure: That the regulator can handle sufficient current to support the camera in
any of its modes. You can add a bigger parallel bipolar pass transistor if you need
more current than the regulator by itself can handle.

Make sure: The final pass transistor or regulator itself has sufficient heat sinking to
dissipate the 3Vdc drop * max camera current = watts. The regulator has to convert
the power lost into heat and will protect itself by cutting the power off till things cool
down if it overheats. But that could result in annoying unreliable operation, so use a
sufficient heat sink to pull excess heat away from it first.

:S:MarkSCoffman