voltage drop on these diodes?

[thebucketmouse]

Hello all, I just made a build but 5 min after I finished it, my microboost driver died However I want to test the diode to see if it still works. Does anyone know the voltage drop across the A140 diode? I'll calculate whatever resistor to use for it, and I have a variable power supply from 0-18V so I can set it to whatever just to test the diode. Thanks

 

[horhay]

it starts lazing around 3.8V, and goes up with the power until around 4.7V, i believe- so a safe testing voltage would be 4V.

 

[Coherent Light]

Mouse is the Current adjustable on the PS?

If it is what You need to do is with both current and voltage at zero connect the diode observing polarity. Crack the current a small amount, and then start to adjust voltage. As the voltage goes up if it stops, add a bit more current. You should have the A140 turning on around 2.5 - 3.0 volts it will not be lasing at this point. crank the current up and at aprox 300ma the diode will start to lase. You can then balance current and voltage, but I would not go over 1.5amps.

 

[Kevlar]

http://laserpointerforums.com/f65/post-your-ma-mw-51432-10.html#post728480

Post #227 :beer:

 

[Bluefan]

Try to use an as high as possible power and value resistor, this way the voltage to current conversion results in less current ripple for the same amount of voltage ripple, also the slight changes in voltage drop are better compensated. I have a 8ohm 100W laying around for testing, works fine.