daguin said:
[quote author=hhspunter link=1220734215/0#4 date=1220763198]some guys have pushed these to about 200ma, and I might like to be able to run it that high every once in a while.
When you go above about 165mA you are entering dangerous territory
Also, turning the current up and down is NOT recommended
Set it and forget it
Peace,
dave[/quote]
I think the straw that broke the camel's back for me to build a laser (and purchase parts!) was when my physics professor said he wanted us to get laser pointers for the lectures (he does unofficial quizzes to check our understanding, he wants us to use the laser pointer to point to the correct answer). I always wanted to build one and now I have a legitimate reason to. So I would like to be able to turn down the power for class, so I don't blind anyone. I now think I'll make the maximum current be somewhere around 150 mA, which means (if I'm using the lm317) the resistor should be 8.33 Ohms, or however close I can get it. I'm thinking I'd like to be able to turn it down to about 5mW (my professor said that's the legal limit). Will a blu-ray diode work with this small amount of power?
And about the not adjusting the current, why is it not recommended? I remember reading that the pressure from the screwdriver can cause funny things to happen with the pot, but why else is it not suggested?
My parts are in the mail, I'm excited!
EDIT: Okay I just reread about adjusting the pot, and from what I read, there are problems when you adjust the pot while the laser is running. So if I turn it off, adjust, measure current, turn off, adjust, measure, etc, will it be okay?
Also, what current would correspond to 5mA?