LS Question?

[logicnerd411]

The bottom contact of the LS is negative or positive?

 

[Darell]

Of the Arc LS or a Luxeon Star LED?

The bottom of the Arc is negative, and so must be the LED, now that I think about it.... I've never considered that pad to be an electrical contact - just thermal. But I suppose it IS the cathode.

What I know for sure is that I've grounded that pad, and the LED still lights

 

[logicnerd411]

Originally posted by darell:
Of the Arc LS or a Luxeon Star LED?

<font size="2" face="Verdana, Arial">The LS LED. Anyone sure?

 

[B@rt]

About the bare LED:

The anode side of the device is denoted by a hole in the lead frame.
Electrical insulation between the case and the board is required-slug of device is not electrically neutral. Do not electrically connect either the cathode or anode to the slug.

<font size="2" face="Verdana, Arial">Quote is from this pdf: DS25.pdf
The nipple of the Arc LS head is positive...

Hope this helps,

 

[Doug S]

Originally posted by logicnerd411:
The bottom contact of the LS is negative or positive?

<font size="2" face="Verdana, Arial">See this thread:
http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=3;t=004029#000000
Do not extrapolate to the AlInGaP LEDs [red, red-orange, amber] as other have reported that the slug of these is positive. I have not personally verified this.

 

[Rothrandir]

the whitish\bluish\greenish are (only sometimes?)-negative slugs, whereas the alingap (reddish) colors unfortunately (and stupidily) have a positive slug.

if you are connecting a non-alingap luxeon to a heatsink connected to the negative power supply, it should be ok...even if you connect more in parallel (series is probably bad)

when using alingap ones, it is a good idea to use a non-conductive surface for heatsinking.

 

[logicnerd411]

I'm still confused. Here's the situation:

I ordered a bare LS from Wayne Y. at the CPF Shop. I am trying to put it into a small tube that holds a 123A. Can the battery nipple (positive) touch the BOTTOM of the LS? Or is it the sides that stick out that are positive? Some jargon here I don't understand...

 

[Doug S]

Originally posted by logicnerd411:
I'm still confused. Here's the situation:

I ordered a bare LS from Wayne Y. at the CPF Shop. I am trying to put it into a small tube that holds a 123A. Can the battery nipple (positive) touch the BOTTOM of the LS?

<font size="2" face="Verdana, Arial">No.

 

[Rothrandir]

you need to join the slug to a heatsink with a thermal adhesive.

 

[B@rt]

You need to electrically isolate the housing of the led (make sure you heat-sink it though...) and use the terminals to supply power.

 

[Darell]

Now I see what the question is. The little wings that stick out the sides are the contacts. The bottom metal plate is for heat-sinking. This NEEDS to be sinked. The positive wing is the one with the complete "o" next to it in metal. The negative wing is the other one. Don't use the bottom plate as the positive contact.

 

[Rothrandir]

what color are you using?

 

[logicnerd411]

Originally posted by darell:
Now I see what the question is. The little wings that stick out the sides are the contacts. The bottom metal plate is for heat-sinking. This NEEDS to be sinked. The positive wing is the one with the complete "o" next to it in metal. The negative wing is the other one. Don't use the bottom plate as the positive contact.

<font size="2" face="Verdana, Arial">OH!!!!!!!!

So it MUST be heatsinked? Is there a chance of survival without one?

 

[Rothrandir]

well, if you drive it at around a volt maybe...

 

[logicnerd411]

Where can I order one? Can I use a penny?

 

[Rothrandir]

penny's aren't really a good idea...they aren't as thermally conductive as regular, and they are not nearly smooth enough.

aluminum and copper and silver are the best.

...what exactly is it that you are doing? a little more information would help. you can even use an aluminum sheet cut down to size or a copper endcap that they use for copper pluming.

 

[logicnerd411]

Well, I'm putting it into a lipstick case with 1 123. How would I go about doing this?