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How do i make my diode last longer

M

Maxx

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im planning on making a laser for my self, it will be my first. i want to know how i can increase the life span of it.

i think that it was VaThInK on a different forum that said a 650nm diode cooled (i guess that means with a heatsink)will last 10 hours, how can i increase that


how much do you guys think that this would help with the heat sinking? http://www.laserpointerforums.com/forums/YaBB.pl?num=1193790319/0 kenom says that it has a think piece or aluminum, will that be good enough for my laser for my laser?
 





rog8811

rog8811

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Life is as much down to drive current as temperature, a well fitted heatsink will increase lifetime, a TEC will most likely increase it more. If you put too many ma's into it no matter how you cool it the LD will have an early death.

I would assume you are going to use DDL's LM317 driver? if so with 5ohm resistor, heatsink and a shortish duty cycle it will live long and prosper, if you go down to 3ohms it would be more likely to last a shorter time......

It is your call at the end of the day, both setups will light matches, the lower ohm setup will do it quicker. It is all down to trade offs, read up on the various threads and decide which way you want to go.


The Kryton barrel will give you very good thermal transfer away from the LD as it is directly fitted to the aluminium so it would be a good start.....still down to how hard you drive it though......
I hope that helped

Regards rog8811
 
C

Chris.

Guest
10 Hours is a bit short IMO, I'd expect 1000 Hours out of a properly protected and duty-cycled DIY?
You would be seriously overdriving it to get 10 hours, it can last 10ns with all the cooling in the world if you want; Depends how hard you drive it.
 
Gazoo

Gazoo

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Maxx said:
what do you mean how hard i drive it?
Click to expand...

How much current you put into it...and I doubt VaThink got 10 hours out of that diode. Do you think he sat there and timed it every time he turned it on??? ;D

The diodes life will be dependent on the diode, how much current you drive it with, how well you keep it cool, and the duty cycles you subject it to.
 
J

jay210683

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a good driver would be ddls you can change the ma going into the ld
look at stonetek.org
for the heatsink ensure you geta really tight fit or use thermal grease
 
P

pseudonomen137

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MTTF if you're running the diode WITHIN SPEC, and AT ROOM TEMPERATURE is normally in the 5,000 to 10,000 hour range for that type of diode. Normally though, people are taking 80mW CW diodes and running them 200mW+ output without proper heatsinking, that's why you're getting diodes that suddenly fail after a few seconds-hours of use.

What everyone is saying about driving it properly is don't be a bonehead. The diode was made to take a certain amount of power, and output a certain amount of power. If you're going to push that, you pay the consequences. Figure out how much current the diode is made to take (should say on the spec sheet for the diode), and build a current-limited driver like the Daedal circuit everyone is talking about and you should be relatively well off.

.... or never use it :D
(actually, you'd need some ESD protection in that case!)
 
M

Maxx

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well im getting my diode out of a dvd burner, where would i find the spec sheet of that?
 
Gazoo

Gazoo

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Maxx said:
well im getting my diode out of a dvd burner, where would i find the spec sheet of that?
Click to expand...

There really is no way to know unless the diode is marked and you can look it up. Which DVD burner are you thinking of harvesting the diode from???
 
Gazoo

Gazoo

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He was not using the ND filter on the meter...I have the same one. But I am sure he was close to it. I drove mine with 600ma's using a TEC until it died. It was fun while it lasted.. ;D It was putting out 350mw's.

Unfortunately no one has been able to find any specs on the open can diodes. So we have used what VaThink did as kind of a quide..I do think using open cans all started with him and his posts at CPF.

There are many recent posts in the Experiments and Modifications section of this forum regarding the use of open cans and TEC's. If you have not looked there I suggest you do and read through the posts. ;) Open cans are fun...I am running one with 350ma's and it is putting out almost 250mw's using a TEC.
 
A

a_pyro_is

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Maxx said:
how does ma's affect lasers anyways
Click to expand...

First, read these Basic EE Lessons Taking special note of the 'Basic Concepts' and 'Elements' sections.

Second, read Sam's LASER FAQ Taking special note of the sections on diode and DPSS lasers as these are the types most common on this forum.

That should give you a good start.
 
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