Someone please post a pic of....................

[G Pilot]

the resistor on the Arc board. I want to boost the power but I have no idea where to solder a resistor (oh yeah and what was the resistor I needed to use /ubbthreads/images/graemlins/wink.gif) I really need a walk thru with pics if possible.
Thanks folks.

 

[MenaceSQL]

/ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/popcorn.gif

 

[Floating Spots]

Re: Someone please post a pic of..................

I don't have a picture for you, but I can tell you how to select a resistor. That particular IC uses a feedback voltage of 50mV. Thus the current across the resistor must develop 50mv to regulate. V(Voltage) = I (Current) * R (Resistance).
So You know that V = 0.050 volts.
Thus, if you want the stock current of 333 mA, you would divide 0.050 volts by 0.333 amps, which equals ~ 0.15 ohms.
So from that direction, you can find the resistor from the desired current.
The other direction would allow you to find the current from a standard resistor. This would be dividing the 0.050 volts by the known resistor. So if we have a 0.15 ohm resistor this would be 0.050 volts divided by 0.15 ohms, which equals 0.333 amps.

Did this make any sense????

 

[G Pilot]

Re: Someone please post a pic of..................

Yep that part is very clear, thanks. Now all I need is to know where I solder. The Arc board doesn't have anything that looks like a resistor (atleast to me).
Thanks again.

 

[LitFuse]

Re: Someone please post a pic of..................

"R15" is the resistor.


Peter

 

[Floating Spots]

Re: Someone please post a pic of..................

I'm stealing an image from EvilLithiumMan's post in the Re: Help : Just killed my new BB750-T-Lux3 ??? thread.
This is of a badboy, which is the basis for the Arc circuit.
(The same items are on an Arc board, just in different places).
In this picture, the resistor is all the way on the left.

 

[G Pilot]

Re: Someone please post a pic of..................

Ok I used this web page to identify what resistors I had and mine was red black black gold. http://www.dannyg.com/examples/res2/resistor.htm
I have a .20 ohm resistor, which would make the Arc board jump to:
.050/.20 = .25
.25 + .333 = 583ma
Is this right?

 

[darkzero]

Re: Someone please post a pic of..................

Ok here you go, I borrowed the pic from one of Belyo's posts regarding warm whites. The resistor to change is the easily seen Green R15 as stated before. Or if your adding one, it would go in the empty space right next to the R15 (.15). Using Wayne's Resistor Calculator makes it simple.

 

[G Pilot]

Re: Someone please post a pic of..................

Thank you.....off the subject.....I have a 3 watt and it is very dim. What does a blown Luxeon do? Does it still light up or what. I put 3 lithium AA in a Streamlight 3AA w/ a 3 watter. It lit up real bright, then went dim. There was light, but real dim.

 

[lambda]

Re: Someone please post a pic of..................

[ QUOTE ]
G Pilot said:
Thank you.....off the subject.....I have a 3 watt and it is very dim. What does a blown Luxeon do? Does it still light up or what. I put 3 lithium AA in a Streamlight 3AA w/ a 3 watter. It lit up real bright, then went dim. There was light, but real dim.

[/ QUOTE ]

Not a good sign, but have you checked just to make sure a cell isn't bad? If all the batteries check out, then sounds like you cooked the Luxeon. What kind of heatsinking were you using?

 

[G Pilot]

Re: Someone please post a pic of..................

Yes the batteries are new (checked on a DMM).I used a the stock luxeon star aluminum plate + the stock stainless plate under that + home made aluminum plate under that, all epoxied together. It was a good 1/2 to 3/4 thick!