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How long will a diy red live when running at 180ma

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I've had very bad experiances with ld's dying, most of the time cause i put to much current in them, i never measured but i would guess about 370ma.

This time im buying one more and im going to lower the current to only 180ma, so my question is if i have a full driver with cap and everything should i expect this too live as long as a bought laser, like say 3000-5000 hours?

...lazer... ;D ;D ;D
 

L

likewhat

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Re: How long will a diy red live when running at 1

If it is run below the advertised max current it should live forever. I have had CD burner diodes last for 2 years and counting that are run continuously without ever being turned off. They have very nice commercial drivers and are actively temperature regulated at about 65 degrees F, but as long as the driver is not slammed on and off (i.e. has a capacitor to let the current ramp up) and you dont let it get super hot it should last until you decide to turn the power up and kill it.
 

Switch

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Re: How long will a diy red live when running at 1

What exactly are you doing with those forever on IR diodes? :-/
 

f22warzone

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Re: How long will a diy red live when running at 1

meh how much for thos dvd's your selling : )

j/k but yes what do you do with cd drives on forever?
 
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Re: How long will a diy red live when running at 1

Um, can i have an answer, 180ma is about 40ma over what they say so im wondering how long it will live...

...lazer... ;D ;D ;D
 
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likewhat

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Re: How long will a diy red live when running at 1

Oh, I didnt know what it was rated at, since that is over the rating it will get hotter than it is supposed to and probably have a short life. I dont think you will get a good answer because people generally dont know the life span of things that are used outside of their designed operating conditions, but I have had pretty bad luck in terms of life with running them over their ratings. I tried a few times running some rated at 120 at around 140 and they only lasted a few days (continuously on).

The CD burner diodes are nice because they are near 780 nm which is where a laser cooling transition is located for Rubidium. They were never turned off because the frequency had to be precisely controlled, so once you got the frequency in the right spot never turning them off means they will stay in the right spot.
 
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Re: How long will a diy red live when running at 1

um, 180ma is still a very safe current to be running these at, like kenom has his dorcy flashlights running at 300ma and they will live 3 months easily.

...lazer... ;D ;D ;D
 

spyrorocks

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Re: How long will a diy red live when running at 1

230-250ma is usually what people run the LDs from dvd burners at, right?
 

Gazoo

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Re: How long will a diy red live when running at 1

spyrorocks said:
230-250ma is usually what people run the LDs from dvd burners at, right?
Right if it is at least a 16X burner or a Senkat diode. I am surprised as how well the Senkat diode burns running at only 160ma's.
 

Switch

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Re: How long will a diy red live when running at 1

likewhat said:
Oh, I didnt know what it was rated at, since that is over the rating it will get hotter than it is supposed to and probably have a short life. I dont think you will get a good answer because people generally dont know the life span of things that are used outside of their designed operating conditions, but I have had pretty bad luck in terms of life with running them over their ratings. I tried a few times running some rated at 120 at around 140 and they only lasted a few days (continuously on).

The CD burner diodes are nice because they are near 780 nm which is where a laser cooling transition is located for Rubidium. They were never turned off because the frequency had to be precisely controlled, so once you got the frequency in the right spot never turning them off means they will stay in the right spot.
So you have a power supply that you never took out of the wall outlet for 2 years that powers IR diodes continuously? Why? What for?
 
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Re: How long will a diy red live when running at 1

Switch said:
So you have a power supply that you never took out of the wall outlet for 2 years that powers IR diodes continuously? Why? What for?
Switch, the same post you quoted answers all of your questions.
 

flogged

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Re: How long will a diy red live when running at 1

wooooooolazer said:
I've had very bad experiances with ld's dying, most of the time cause i put to much current in them, i never measured but i would guess about 370ma.

This time im buying one more and im going to lower the current to only 180ma, so my question is if i have a full driver with cap and everything should i expect this too live as long as a bought laser, like say 3000-5000 hours?
370 mA ?! Oh good grief it's amazing they lasted at all. I would never take any of the Sony 16x diodes over 300 mA without active cooling.

The only reason these LDs can be pushed so hard without getting COD (instant damage to end facets) is they're designed to reach these power levels, but PULSED, not CW.

These diodes are rated for a CW power of around 80mW with a 130-140 mA current draw. Beyond about 200-250 mA you reach the point of diminishing returns. Overpowered LDs will often see a widening of the gain, and they sometimes will not look as 'pure' or speckly.

The way we're using these LDs they ARE going to have a shorter life than they are rated at. There are two things you can do to improve their life. First you need good heatsinking. Use thermal paste or glue to assure that heat can escape the LD package to the case efficiently. There is a direct relationship between an LDs lifespan and it's junction temperature. The warmer (above about room temp) the LD gets, the shorter its life. But it's not a linear degradation -- a part that's 2-4x as warm may see an exponential decrease in it's lifespan. For my next burner I'm going to a thermally conductive glue to assure the back of the diode can dump its waste heat efficiently to the case/heatsink.

The other thing you can do is assure the duty cycle remains very conservative, say no more than 1-3 minutes of use before letting it cool for a minute or two. Either that or have active cooling or very good passive cooling (that is a large heatsink properly attached to the LD).

I would suggest trying around 200 mA of current (mine is at 225 mA0). This will give you enough power to burn and increase the life considerably over a diode pushed with more than 350 mA of current.

{EDIT} These LDs may have lifespans of over 10K hours when driven at spec. A well made pointer will still hopefully have a life of 500-1000 hours, which is a LOOONG time for a pointer.
 
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Re: How long will a diy red live when running at 1

Well the reason they were that high is because i never botherd to measrue, altho they were thermal glued to the metel housing they were in. Im still going to keep the next one at 180ma i want one that wont die within a week like most of the others ones do, i always had a duty cycle on it, i only kept it on 2min at the maximum and allowed 1 min to cool.

I might turn it up to 225ma tho, i dont reallly want to go past that point anymore. Id rather have it last 500 hours and not burn quite as good then have it last 2 and burn insanly good.

...lazer... ;D ;D ;D
 




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