Converting 12V to 5V

[slvrstang]

Alright, i have a 12v power switch. I have a 5 volt LED i want to switch on and off. Can i just put a resistor in the middle of the line? Or is there some easier way.


12V-molex switch connector(giving power)

---------
..........0 Yellow wire (12V)
---------
..........0 Black wire (ground)
---------
..........0 nothing
---------
..........0 Nothing
---------

5V molex connector (needs power)

---------
..........0 Nothing attached
---------
..........0 Nothing attached
---------
..........0 Black wire (ground)
---------
..........0 Red wire (5V)

as you can see, when i plug them in together, none of the wires match up. I was thinking of moving the yellow to the red, but thats 12V on a 5V item.

Help the electronic noob
----------

 

[mlr]

http://www.thehardwire.com/articles/index.php?id=2 maybe this will help theres a link to a pic on 2nd post down eres another http://www.virtual-hideout.net/guides/7v_12v_baybus/index.shtml

 

[slvrstang]

thanks for the attempt but i only have 12v and 0v to work with here. Can't i just use a resistor? or does that only resist amps?

OK

R=V/I

R=Resistance in ohms

V=volts

I=amps

i need 5 volts from 12 so it must resist 7 but how do i know how many amps my PSU is giving?

 

[csw3190]

thanks for the attempt but i only have 12v and 0v to work with here. Can't i just use a resistor? or does that only resist amps?

OK

R=V/I

R=Resistance in ohms

V=volts

I=amps

i need 5 volts from 12 so it must resist 7 but how do i know how many amps my PSU is giving?

Hint: elec. engin. school

 

[slvrstang]

or... you could give me the answer, and save myself 6 months of a class i'll never use again?

 

[slvrstang]

come on guys i know one of you knows electricity

I think the formula is Ohms=(V1-V2)/amps

And i have Ohms=(12-5)/amps

Ohms=7/amps How can i check how many amps my LED's draw?