Help(!) with emitter polarity on 5W LS

[tvodrd]

With my delight with the beam with a cut down 30mm optic, I rushed to "pop" the emitter from the pcb so I could finish the design. Stoopid me forgot to note/mark the polarity on the emitter /ubbthreads/images/graemlins/twak.gif, and the 5Ws are different than the 1Ws. Each terminal has an adjacient tab. One tab is about twice as long as the other. Can somebody please please help?

Larry

 

[MR Bulk]

Just hit it very briefly with a low voltage source (it should just start to light up at around 5-6 volts), if it doesn't light up, try the reverse.

 

[Deleted member 684]

Mr Bulk, is the max reverse voltage still 5 volts?

tvodrd, if you have a multi meter, it should have a setting to measure the forward voltage of the LED, if you don't have a multi meter, I suggest you go out and get yourself a cheapo $10 one. I'll be useful in the long run.

 

[MR Bulk]

No, in fact I still have a reversed-lead 5W SE from a previous run but it fell out of a sorted bin along with a some other (normal polarity) emitters, so I simply hit them each with 7.5V from a constant power supply and resorted them. No harm done.

 

[tvodrd]

Thanks guys,
Polarity of this one was correctly marked on the pcb. My Fluke reads open in both directions on even a 1W. I'll check Lumileds site once more and if no luck, will "spark it" after I get it on its new sink.

Larry

 

[INRETECH]

Try using the correct voltage with a series resistor to greatly reduce the current and try both directions

 

[tvodrd]

Thanks again, guys,
6V,10 Ohms and "leopard syndrome." The 5W emitter info on Lumilesds' site shows the same layout as for a 1W, which doesn't match the physical appearance of the emitter on the star. For future reference, the + was the side with the longer tab. The tabs adjacient to both terminals appear to be electrically common with the terminals themselves. I soldered it in including the tabs. My first 5W (and a V3!)-WOW!!!

Larry