Exceeding LED ratings

Just a slight embarrassment and inconvenience unless a mass failure occurs. As I said in one of my posts, I'll be on hand to replace an occasional blown LEDs.

I was under the impression that LEDs failed short (at least under reasonable overload conditions). If you whack them so hard that the wirebond to the die evaporates, then certainly you'll get an open circuit, but my Christmas tree lights (wired in series) appear to work just fine with a couple dead LEDs.

OK, I'll bite. Why is it not _possible_ to use 81 LEDs in series? We use 230V AC here. Not everyone lives in the US.

You obviously didn't get it.

They "GENERALLY" fail short. not always.

They are physically strung on a string 'in series', but are NOT wired 'in series'. Nice guess though. You should probably look first next time before presuming based on appearances.

You are AlwaysWrong ( jack snipped-for-privacy@cox.net )

You are AlwaysWrong ( jack snipped-for-privacy@cox.net )

You are AlwaysWrong ( jack snipped-for-privacy@cox.net )

No, you obviously didn't, even though there was a big fat smiley to make sure your nose would find it.

What did you expect? That's AlwaysWrong ( jack snipped-for-privacy@cox.net )

Ahh... must be like the one I placed, which you all have obviously missed.

At which point the LEDs are being fed DC. GET A CLUE, IDIOT.

Mentioning the line voltage was dumb.

If so, then you mentioning the above was even more dumb. I said you were the epitome of stupid, but I underestimated you. You have reached a new level stupidity that cannot be defined.

Mommy's hamper is calling, DimBulb.

No, he isn't. He never is, as he never takes a position. ALL he EVER does is make retarded, peanut gallery remarks that show him for the total twit that he is. You cannot be much better to carry on a discourse with him in such a vein. You are a true hypocrite.

You said nothing. If you think you did, then you are even more stupid than the twit boy is.

Especially when you did not even make a point... at all.

You are an idiot. You never made an argument, and you sucked up to a complete fool who never makes ANY point in the group, much less any that are valid.

I wonder how may angels could dance on his head?

Piling on Dan's note, heat's the problem, and maybe not as big a problem as you think--your LEDs may be 30mA-rated, not 20mA. T-1 (5mm) LEDs are good for ~75mW, IIRC. Red LEDs have generally lower forward voltage and are therefore often rated for higher current (30mA) as a result.

For example,

Double-current at 50% duty cycle isn't unreasonable. Heatsinking the LEDs helps a lot--short leads, copper pour on the lead connected to the die cup.

HP had extensive literature on overdriven LED lifetime--dunno which one of their spin-offs wound up in charge of it.

-- Cheers, James Arthur

Hi Pimpom, Have you tried one or two at twice the current. A year or so ago.. I was pushing LEDS to see how much light I could get out. Once I got above the rated current I wasn't getting that much more light...Certainly not double for double the current. This was a DC measurement and not pulsed. When cranked up to 50mA, I found a lot more 1/f noise in the LED light output. And if left at

George H.