Thread: power voltage change

look at a adjustable voltage regulator...
http://www.radioshack.com/product/in...ductId=2062601
that with a couple of caps and resistors (maybe $5 worth of parts)

the first diagram in this link should help you out. Just take into account that your car probably puts out more than 12v and should be metered to check. Thats why the pot(R3) is included.
http://www.uoguelph.ca/~antoon/circ/ps-lm317.html

there may be another solution like a resistor, but you would need to meter your batt with the car running and use Ohm's Law to figure out the resistor, but it is inefficient and may cause problems down the road due to heat.

(if your voltage is 14v and you want to drop down to 9v i think it would be about 250 Ohms resistor??? i think the wattage is a 0.1 watt resistors?
Maybe someone can correct me if im wrong but...
V=I*R V=5 due to the difference in voltage
I=.02 amps so....
V/I=R ------5/.02=250
that is 250 ohms for the resistor and to figure out power dissipation

(I*I)R=P I equals power consumption
(.02*.02)250=P
P=0.1watts

again this system would require a 14v system and would change and not be as consistent as a voltage regulator.)

Hope this helps

Great, thats what i needed to know.
Thanks for the help.

What about the output current?
the positive voltage regulator states is has an output of up to 1A, will that affect me since all is needed is 200mA?

ok good, thanks
Does anyone know what could be used to encase electronics like a circuit board that would keep it weather proof but not short out the electronics. I know like on a automotive relay if you look at the bottom of some of them there is some kind of clear or yellowish epoxy or plastic that is used to seal it. Does anyone know where i could get something like that or what i could use for it?

Thanks

i found that out but i am having trouble on where to find it. What i find on the internet is companies that look like they sell it to other companies, i was hoping to find something local at a hardware store like menards or somewhere like that. Any ideas? I tried the eletronic supply store where i bought the positive voltage regulator and they didnt have anything for that.

Thanks