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I bought a bag of 1 w led lights and a 25 ohm potentiometer. Can you guys verify my wire diagram for me?

I was going to use a yellow 12w and ground from the p/s...

Is the 25 ohm pot the right choice for these?

See attachemnt...

THANKS!!

Bill

wiring looks right bill, but you may want to add another fixed 8 ohm resistor (minimum) before the pot, so you dont blow out the leds, when the pot it at its lowest setting.

also you may want to get a larger pot, so you have more range of brightness/dimness adjustment.

I have a 50ohm pot plus a 10ohm fixed, for a total of 60ohms, and its still pretty bright at 60 ohms.

this is at 10ohms full intensity

Thank you again!!

Bill

Wow the 50 ohms are kinda hard to find, radio shack doesn't have one without a super long shaft.

Mouser had a 4 watt 50 ohm, I could use the 4 watt right?

Bill

yes that's fine, i got mine from mouser, let me find the part number. this is what i used but If I had to do it again, I would get something a little higher resistance so could dim the led more.

http://www.mouser.com/Search/ProductDet ... 32R500B1A1

http://www.mouser.com/Search/ProductDet ... -PKA50B1/4

As you can tell, I'm not an electrician, if the 3 bulbs are 1 watt each, does that mean that the resistor and the pot can be no more than 3 watts?

Bill

means it shouldn't be any less than 3 watts in our situation because the resistors need to dissipate minimum of 3 watts. If you get a higher watt rating, it just helps in my opinion, it wont run as hot, and maybe prolong the life of the resistors.

The more watt the brighter the bulb then? but to much and the bulb will be too bright at 100% right?

bplemmons wrote:The more watt the brighter the bulb then? but to much and the bulb will be too bright at 100% right?

yes a higher wattage led means a brighter bulb. not sure what u mean by the second statement. The led(s) is usually set at that wattage rating, you can't make it brighter without burning it out. You can run it at its rating or lower.

as far as resistance, wattage is dissipated as heat in resistors, so if you have a 3 watt resistor your pretty much at the limits of that resistor.
the pot doesn't determine how many watts your led will receive. That's just want its rated for (ie it will dissipate up the rated amount). Just because the pot resistor is 5 watts doesn't mean that is what your leds will be receiving.

changing the resistance of the pot is what makes the led bright or dim,

I worded that poorly,

So if I have 3 1 watt leds wired up in series I should not let more that 3 watt come into the leds? if so, then I should look for a resistor and pot to be rated at no more than 3 watt?

Sorry for all of the questions but I do want to learn something....(and your guys are great)

no your misunderstanding, the 3 watts is all that your circuit will use. you wont be adding more wattage unless you add more leds.

Thanks so much,

What is the picture of in your profile anyway?

bplemmons wrote:Thanks so much,

What is the picture of in your profile anyway?

my cnc router

You may want to invest in one of these:

http://www.amazon.com/microtivity-750-p ... breadboard

They are extremly handy for testing setups before commiting to solder.

Can I power the bread board with a 9v battery or do I use my p.s from the printer?

Use a 9 volt battery. Do a Google search for Basic Electronics Tutorials and study those.

bplemmons wrote:Can I power the bread board with a 9v battery or do I use my p.s from the printer?

Either really, Just supply power to a pair of rows then grab it and put it where you need it. There are a ton of breadboard turorials out there as well.