Oh I'm a donkey as u can probably tell by now

 

by the way, how am i suppposed to attach the led to the heat sink...

 

by the way, how am i suppposed to attach the led to the heat sink...

drill/tap it and use screws or bolts and heatsink compound..

 

man no wonder you guys are all technical about your stuff this is getting complex. a lot of variables now

 

now that i think about it... would the heat sink be part of the circuit ??

 

No, heat sink is not part of the circuit. It is simply a radiator to transfer heat from LED to the environment.

 

ok i thought i would have to ground it or something.. i wonder what stops the current from going into the aluminum

 

ok i thought i would have to ground it or something.. i wonder what stops the current from going into the aluminum

Heat sink does not touch the contacts, therefore there is no current going into the aluminum.

 

Using a fixed resistor and looking at the possible forward voltage drops of the LED the current changes considerably.
12V supply..
If R = 5 ohm
if Vf = 9
12-9Vf=3/5= .6A (running at 60% of what its rated for)
or
if Vf = 11
12-11vf = 1/5 = .2A (running at only 20% of what its rated for)

If thats ok with you then go right ahead..

All depends how fine you're cutting it, for most purposes its an adequate arrangement - if you're trying to squeeze every last milliwatt out of a power LED, its best to have more headroom - but then you waste more power.

The OP is working to a budget - compromises are inevitable.

 

All depends how fine you're cutting it, for most purposes its an adequate arrangement - if you're trying to squeeze every last milliwatt out of a power LED, its best to have more headroom - but then you waste more power.

The OP is working to a budget - compromises are inevitable.

yeah I wasn't aware of the "tight" budget ..
I only recommended the meanwell to "do it right".

 

ok so the light came in the mail today. i went to EPO and they suggested i do NOT get a resistor so i saudered the light to the wires and they dont all stay on.. the chips are 3x3 after about 5 seconds ... the middle row goes out, then the first row goes out after about 30 seconds... any ideas why ? is it the chip or did i do something wrong

 

How many led?

 

1 10w 1050mA 12v

 

So after all this discussion you just hooked it up directly to the power supply without any form of current limiting?
If so its probably garbage now.
and whats "EPO"

 

OP blew the LED's after every one suggested about a series resistor.
The EPO guy is better I presume.

I wonder what was the supply voltage.

 

12v 1.5 amp

 

Does they light up now ?

 

Yes all the chips still light up but they go out quickly

 

Yes all the chips still light up but they go out quickly

You MUST have the resistor. (or other method to limit the current through the LED)
DO NOT plug it in again until you have the resistor in place.

 

Yes all the chips still light up but they go out quickly

On a second hand PC tower case I bought a while back, I noticed that after a while the PWR LED started to flash - slowly at first, but getting faster.

On closer inspection I found someone had wired the PWR LED straight to a Molex connector with no current limiting resistor.