Finally done it (back again)

[jonrobertd]

Re: Finally done it (got a few ?s now)

Is it normal for the diode to get a deeper red at a higher mA input, it seems dimmer but deeper.
Driving it at 185ma it is a bright red, but at 220+ it gets deeper red and I was wondering if I am gonna kill it, or its normal. Also sorry no beam shots yet my camera doesn't take good shots.

 

[daguin]

Re: Finally done it (got a few ?s now)

Is it normal for the diode to get a deeper red at a higher mA input, it seems dimmer but deeper.
Driving it at 185ma it is a bright red, but at 220+ it gets deeper red and I was wondering if I am gonna kill it, or its normal. Also sorry no beam shots yet my camera doesn't take good shots.

Diodes can and will shift in wavelength at different current inputs. This alone is not an indicator of trouble. Which diode is it? For the vast majority of red diodes we use to make lasers 220mA would be considered a very conservative current. How many mA is represented by the little "+" after 220?

Peace,
dave

 

[jonrobertd]

Re: Finally done it (got a few ?s now)

well after the little freak out I went to testing, my battery was dying, god I feel dumb.
but it's a LG 22x burner and I was gonna go to 300ma but I have it with 5 ohms now so 245ma max (built my own testor with 4 IN4004 diodes and a 1 ohm resistor), but a 22x should handle 420ma correct?

 

[daguin]

Re: Finally done it (got a few ?s now)

well after the little freak out I went to testing, my battery was dying, god I feel dumb.
but it's a LG 22x burner and I was gonna go to 300ma but I have it with 5 ohms now so 245ma max (built my own testor with 4 IN4004 diodes and a 1 ohm resistor), but a 22x should handle 420ma correct?

420mA has shown to be a very good current for these diodes.

 ;D Yep!  ALWAYS check the batteries ( I learned that the hard way)  

Peace,
dave

 

[jonrobertd]

Re: Finally done it (got a few ?s now)

Ok got another ?
Using DDL driver and formula for that is 1.25v/3.2ohms=390ma correct? (pot is not all the way up to max it's a hair off)
So what is the formula to get ma=mw?
And how long can I run continusly, my heatsink is a 1 inch cube of aluminum, see pics on pg 1.
Oh I can light black, blue, and red matches instantly at 18 inches.

 

[laserman55]

Re: Finally done it (got a few ?s now)

well mine is only puttting out a max of like 230mA

 

[jonrobertd]

Re: Finally done it (got a few ?s now)

Ok yours is with one 10 ohm resistor
In order to go higher in ma you must go lower on resistance.
1.25/10 = 125ma so you have maxed out the pot to get 230ma
If your resistance is different please post it.
Better than that post a few pics up for me to look at, top and bottom of driver, and we will get to the problem.
(looked at the pic on other thread saw 1 10 ohm so you are maxing out something and may have a short also what pot is that)

 

[jonrobertd]

Re: Finally done it (I killed it by sneezing)

Well I was soldering my diode to the microdrive and sneezed and ripped the pin out of the diode.
Ordered 2 more drives so be back in buisness in a few days.

 

[laserman55]

Re: Finally done it (I killed it by sneezing)

ok well sorry its been i while since i posted but i am using 2  10 ohm resistors
after the pot

 

[jonrobertd]

Re: Finally done it (I killed it by sneezing)

Thats OK, well with 2 10 ohms you have 5 ohms so thats 1.25/5=250 so with the pot in play 230mA is near right, so to get higher mA you need to get lower resistors. With a 20x diode you should be able to get near 420mA safely so go to 3x 1 ohm resistors in series (end to end to end) to get near 416 mA.

 

[laserman55]

Re: Finally done it (I killed it by sneezing)

wow i wish i had known that earlier i killed the diode i think
its putting out a really dim light

 

[jonrobertd]

Re: Finally done it (I killed it by sneezing)

What happened? Maybe it's not dead. Though it sounds like it :'( .

 

[flogged]

Re: Finally done it (I killed it by sneezing)

Looks good. Happy lasing.

I see you're using the same radioshack potentiometer I used in my DDL circuits. What I found is over time I had to keep adjusting the pot to keep the current reaching the diode constant. Apparently the 'wiper' in the pot oxidizes, which increases its resistance. Once I settled on a current to drive the laser at I bypassed the pot, replacing it with a fixed resistor design to get around this

You might want to meter the lasers current use after a couple of hours use to see if it's drifted.

 

[jonrobertd]

Re: Finally done it (I killed it by sneezing)

Thanks for the tip, I got rid of the pot though and have new diodes so I am back in business YEAH!
Microdrive @ 420ma on a 22x lg long open can!
16x on DDL home built driver @ 250ma!

 

[jonrobertd]

Ok so I have some Ideas time to post them:
1: A heat sink made from an old P1 heat sink by drilling a 1/2 inch hole centered on the mating surface w/fan
2:Thermal epoxy by mixing epoxy and Arctic Silver 5 (gotta test if it conducts electricity when cured)
3: Applying some sort of Heat sinking into the Aixis module for the driver (white cheap thermal paste?)
Ok comment time.
Oh and I feel I should keep all posts relevant to my lasers in this thread rather than cluttering up the forum, that is why I keep posting it all here.

 

[fatboyslim]

Nicely Built