Have I fried my diode?

[CRenzi]

Hello, first post here, I hope you gals and guys don't mind if I start right off the bat with an appeal for help.

You see, I found in my assorted knickknacks a couple of laser diodes, Blu Rays I got from these guys a couple years back. I reckon they are the 405 nm, 150 mW variety

I got around building a driver for these things, copying it from this same forum. I believe it was this one:

Since it didn't work, I tried several others, to no avail. Problem is, a couple of times the diodes DID lase, but I was never able to replicate the event.

So, I would really like to ask you:

• How can I be sure that the diodes still work?*
• Can I divine in some way the specifics of the diodes?
• Is there some foolproof driver module that even I can build?

Thanks in advance

*It occurred to me to test the diodes with a couple of AA batteries, that is, 3.2 V: they produce a feeble blue light.
Still, all the driver circuits I built did not work, so could you suggest any driver that could work?

 

[norbyx]

That feeble blue light you see is what is called LEDED diode, it emits light but it doesn't lase anymore.
My personal opinion you fried the diodes. Probably due to some high amperes in the imput.
The lasers are current sensitive not voltage, so if you give them too much current they die.
Only way to test them would be with a power supply, but since you already tested them with a battery you probably fried them all...

That is just my opinion, might be wrong, maybe someone else has other opinions...

BTW a post in the welcome section takes about 2 min. I would do it if you plan in receiving more answers.

 

[hwang21]

Norbyx,

What does LEDED mean? What about an LED'd diode?

 

[norbyx]

It means it emits light just like a led but it doesn't lase.

 

[CRenzi]

That feeble blue light you see is what is called LEDED diode, it emits light but it doesn't lase anymore.
My personal opinion you fried the diodes. Probably due to some high amperes in the imput.
The lasers are current sensitive not voltage, so if you give them too much current they die.
Only way to test them would be with a power supply, but since you already tested them with a battery you probably fried them all...

That is just my opinion, might be wrong, maybe someone else has other opinions...

Welp, there goes my faint hope of not having wasted money... I suppose I'll have to start from scratch. I tried yet another driver, the one from the guys that I think I bought the stuff from. It's been a while. Anyway, here it is:

The diodes didn't lase with this setup either, so if you reckon this driver is ok then I think I can safely say the diodes are destroyed.

BTW a post in the welcome section takes about 2 min. I would do it if you plan in receiving more answers.

Right you are. I will do so forthwith.

 

[chipdouglas]

what was your input voltage, and what source of power were you using??? The odds are you did fry your LD's, but there is always a small chance you are powering it incorrectly.

Michael.

 

[CRenzi]

what was your input voltage, and what source of power were you using??? The odds are you did fry your LD's, but there is always a small chance you are powering it incorrectly.

Michael.

Uuuh... I should probably go with what I didn't use, it would be shorter.

Anyway, in no particular order, I used:

• Two AA batteries in series, for a total of about 3.2 V. This made the diodes lase
• The two aforementioned circuits, powered by a 9V battery
• The 9V battery alone (I know, dumb, but I was starting to get pissed)
• Some other circuits, mostly variations of the former two ones, with variable resistors connected to the LM317. I'm sorry but I just kept making circuits off some diagram or other I found online and dismantling them when I obtained no results

Thanks Michael, but looking back at yesterday's afternoon I'm losing my optimism. Point is, I had built a driver before, and it worked fine: I didn't approach this expecting problems and got really frustrated.
Guess I lucked out back then.

 

[norbyx]

Uuuh... I should probably go with what I didn't use, it would be shorter.

Anyway, in no particular order, I used:

• Two AA batteries in series, for a total of about 3.2 V. This made the diodes lase
• The two aforementioned circuits, powered by a 9V battery
• The 9V battery alone (I know, dumb, but I was starting to get pissed)
• Some other circuits, mostly variations of the former two ones, with variable resistors connected to the LM317. I'm sorry but I just kept making circuits off some diagram or other I found online and dismantling them when I obtained no results

Thanks Michael, but looking back at yesterday's afternoon I'm losing my optimism. Point is, I had built a driver before, and it worked fine: I didn't approach this expecting problems and got really frustrated.
Guess I lucked out back then.

After reading this last post there is no question.... diode is dead.... you killed it, if not with the driver, or the AA, you shot it dead with that 9V directly hooked... :gun:

 

[CRenzi]

After reading this last post there is no question.... diode is dead.... you killed it, if not with the driver, or the AA, you shot it dead with that 9V directly hooked... :gun:

Well, isn't that a weight off my mind?

Anyway, I have to ask: why do you think it failed to work? I mean, these circuits worked the first time around, and I did follow the schematics, I'm pretty sure of that, so what would be your guess?

 

[norbyx]

A bit hard to say. Just as an example just yesterday I had a diode fail me, I had a diode that was working fine, I had a bad driver, I bought a new driver, I installed the diode (that was tested a week ago. I turned the laser on and Boom.... the diode leded. Why? no idea, maybe static, I just don´t know. Everything was done properly.

 

[BShanahan14rulz]

the two AAs in series doesn't make the diode lase anymore?

If it's dim, is it dim with a hot spot, or is it evenly dim all across the raw output?

 

[CRenzi]

A bit hard to say. Just as an example just yesterday I had a diode fail me, I had a diode that was working fine, I had a bad driver, I bought a new driver, I installed the diode (that was tested a week ago. I turned the laser on and Boom.... the diode leded. Why? no idea, maybe static, I just don´t know. Everything was done properly.

Oh well, I suppose stuff happens. BTW, when a diode LEDs (I don't actually know how to spell it) is there any particular sign you look for? Like, a flash of light? Or complete lack thereof?

the two AAs in series doesn't make the diode lase anymore?

If it's dim, is it dim with a hot spot, or is it evenly dim all across the raw output?

Well, I don't know if it lases or not. It just make a light so feeble that I was only able to see it in the dark. And no, I didn't look directly into it, I angled it towards my finger.

 

[scumbagatheist]

Guys, maybe I am WAY off base here, but it kind of sounds like a lack of voltage is the problem. A feeble 3.2V from two AAs that are supposed to power a >6Vf diode?? To me, it seems like a no-brainer that it's a lack of juice. But, the 9V could have been way more than the driver could take. The driver may be faulty now, but may have let the diode live.

I would suggest finding someone with decent test equipment near you to test both the diode and the driver. I'd do it for you, but I'm in the US...

 

[BShanahan14rulz]

Well, I don't know if it lases or not. It just make a light so feeble that I was only able to see it in the dark. And no, I didn't look directly into it, I angled it towards my finger.

I think I had you confused with someone else. After re-reading, I see you are working with 405nm.

This sounds like LEDed output, BUT 3V may still be under the lasing threshold for your particular diode, in which case it would be expected to only glow dimly without lasing. I've only been able to find info on higher powered 405nm laser diodes, but those higher powered ones don't even start conducting until >3V, closer to 4V.

The strange part about that is that you said it worked before on 2xAA. Perhaps if you find some fresh AAs to test with, you can be sure that the diode is not working as it was. Or perhaps you bought several diodes, and one happens to be freaky efficient? But, yeah. If you can't get it to do what it did before, on 2x unused alkaline (not heavy duty) AA, likely the diode has been damaged.

 

[chipdouglas]

no i'm pretty confident it is a voltage problem and or a fried diode via direct drive. if you used 2 aa's in series with a drive you are no where near close enough in terms of voltage. I believe a 405 needs 4.5 v all to itself, and the driver needs like 1.25v.
the rectangle 9v batts are pretty much useless in this hobby. so don't use them anymore.

use your driver and used good batteries and a have your minimum voltage be over 8v.

then come back.

Michael.

 

[CRenzi]

Guys, maybe I am WAY off base here, but it kind of sounds like a lack of voltage is the problem. A feeble 3.2V from two AAs that are supposed to power a >6Vf diode?? To me, it seems like a no-brainer that it's a lack of juice. But, the 9V could have been way more than the driver could take. The driver may be faulty now, but may have let the diode live.

I would suggest finding someone with decent test equipment near you to test both the diode and the driver. I'd do it for you, but I'm in the US...

Thanks man, but yeah, the way things are here I'm better off learning how to do it by myself.

I think I had you confused with someone else. After re-reading, I see you are working with 405nm.

This sounds like LEDed output, BUT 3V may still be under the lasing threshold for your particular diode, in which case it would be expected to only glow dimly without lasing. I've only been able to find info on higher powered 405nm laser diodes, but those higher powered ones don't even start conducting until >3V, closer to 4V.

The strange part about that is that you said it worked before on 2xAA. Perhaps if you find some fresh AAs to test with, you can be sure that the diode is not working as it was. Or perhaps you bought several diodes, and one happens to be freaky efficient? But, yeah. If you can't get it to do what it did before, on 2x unused alkaline (not heavy duty) AA, likely the diode has been damaged.

Actually, no. I could have put it down better, what I meant is that I already made a driver with a 9V block battery to power a similar diode and obtained good results (i.e. it worked).
I just read somewhere else in this forum that two alkaline AAs could be used to briefly power a diode without damaging it. I hoped to see whether the driver was faulty or the diode.

no i'm pretty confident it is a voltage problem and or a fried diode via direct drive. if you used 2 aa's in series with a drive you are no where near close enough in terms of voltage. I believe a 405 needs 4.5 v all to itself, and the driver needs like 1.25v.
the rectangle 9v batts are pretty much useless in this hobby. so don't use them anymore.

use your driver and used good batteries and a have your minimum voltage be over 8v.

then come back.

Michael.

Just to be sure, by "good batteries" you mean alkaline AAs?
How about transformers? Or PSUs?
I don't mean to be nitpicky, it's just that I never considered that variations in battery type could be important.