Gazoo said:
[quote author=Daedal link=1183788027/30#31 date=1183840655][quote author=Kenom link=1183788027/15#29 date=1183840224]Merideth does sell a driver board that will work for this! problem is it's expensive as HELL! $49.00 it will fit into a pen style laser barrel.
http://www.mi-lasers.com/cgi-bin/sh...hstart=0&template=Templates/SearchResult.html
I'm also looking at a driver board for a LED flashlight that might work with a little modification.
http://dealextreme.com/details.dx/sku.3160
Since I am not that electrically knowledgable I'm having to ask other's if the driver boards I've mentioned will be sufficient. I will let everyone know when I find out more.
The first board doesn't tell you what the output voltage is, the second board I think would be great... Especially the way they have it pictured with nothing on there except for the ramp chip and the diode
I was thinking of working on one these... I'll have to do it sometime considering I have a few lying around gutted from other flashlights
--DDL[/quote]
Hello Daedal,
I have learned to think in terms of current when playing with diodes. Voltage doesn't matter to me and I hardly even look to see how much voltage I am applying. I always monitor current when playing around.
What Kenom is saying about driver boards providing stable current to the diode is true. However, one can get by using the proper resistor ( we are on exactly the same page with that one) and a capacitor.
I have been using a driver board on my home made laser and it is still running the same as the day I put it together. The driver I am using isn't adjustable. However with 4 nimh batteries it provides 240ma of current to the diode. I guess my point is by using a driver board, the diode is likely to last much longer, at least this has been my experience.
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I definitely agree with you... The only thing I am thinking about here is wattage... Diode output is measured in mW... and that is Current * Voltage... 1W is 3V * .333 Amperes. If the diode is fine running at 2.5V at 300mA then that's 750mW, putting out close to 250mW and giving off 500mW as heat dissipation. If you power it at 6V at 300mA then it's putting out a steady 250mW as light and not having a problem... but all that excess is being given off as heat thus requiring more cooling. At this point it would be putting out 1550mW of heat! If the batteries supply 1.2V each then it's a bit less at 1120mW of heat... That is still more than double what the diode was made to give off... That can be limited using a voltage splitting resistor using the right values. The resistor would be giving off some heat though... which would or would not be as much as the diode depending on the resistor itself...
Again... the diode is fine giving off that much heat as long as it is running with something to give the heat off to (like an AixiZ module with some thermal epoxy) and a reasonable duty cycle. It would definitely not be any less than a minute or even more...
Hope that helps;
DDL