Powerful LEDs, their forward currents and flashing.

Hi Everyone,

Im working on a project at the moment that requires a bright flash of light. I am reluctant to use xenon flash tubes, like camera flashes, I would much rather use LEDs if possible.

I have done experiments with P7 emmiters, rebels and stars, and I think the P7 is just about bright enough.

My question is, the P7 seems to want about two amps from my PSU, however I think this may be above its rated forward current. What im wondering is weather this really matters, the LED will be on for about half a second, and the flash will be repeated maybe once every 3-4 seconds. The LED does not get hot at all flashing on so quickly.

If the diode does not get hot, is it OK to run it at higher currents for more light? Is it merely the fact that the LED gets hot and burns out that gives it its current rating? Will running it at a higher current damage it in ways that can't be seen until its all too late?

I guess I could do away with any current limiting resistors in my circuit and just zap it with the full power of the battery for the half second, but will all my flash modules start dieing because of it?

Thanks for any help,

Pete.

2 Ampere is below the specification level of a P7 (that is 2.8A).

The bonding wires can deal with a lot more current. I was able to push 8A through them without them burning through (of course they did blue out a lot, but this is a thermal issue that should not matter with low duty cycles).

I've experimented with my P7 flashlight, get the heatsinking down good and you can use up to 5 amps for short bursts like less than 5 minutes or so and get more light, beyond 5 amps or so you don't get any more light though. Even 4 to 5 amps you only get a little bit more light so I'd draw the line at 4 amps for continuous use, and really since you don't get more light at 5 amps even for flashes I wouldn't push them beyond that since you get nothing more out of them.