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Is this symptom a laser driver issue ?

Accutronitis

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I've been messing around using a IR temp gun and having all the focusing part removed from the laser, with everything removed the brass heat sink fits perfectly in the temp guns opening. I just wanted a way that could tell me quantifiable that the power output was def dropping and when it was dropping off.......

Ok this is what it's doing, For about 15 to 20 seconds the temp gun reads 200 degrees and then after around 15 to 20 seconds it starts to drop very rapidly and at 50 to 60 seconds it by around dropped by half and yet nothing is warm to the touch, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results. and the whole time nothing is even warn to the touch ?

Well you get the idea........

That would pretty much have to be the driver issue wouldn't it ?
 
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Rivem

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Edit: Misunderstood question due to unclear original explanation.

You think the laser in the IR temp gun is causing measurement issues due to a bad driver?

If so, those IR temp guns only have a laser to show you where they're pointing. It has no effect on the measurement. If it's giving you trouble, it's something in the sensor circuit or a faulty sensor.
 
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Accutronitis

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You think the laser in the IR temp gun is causing measurementioned issues due to a bad driver?

If so, those IR temp guns only have a laser to show you where they're pointing. It has no effect on the measurement. If it's giving you trouble, it's something in the sensor circuit or a faulty sensor.
No, I'm using a ir gun as a make shift laser power output meter and it work very well to tell me if the output is staying at the power it started with and it tells me if the output is going up or down and how fast BUT it won't tell me how many watts of course......

The output i'm testing is from a A140 laser diode without any focusing lens.....

Let me put it to you this way...

Ok this is what it's doing, For about 15 to 20 seconds the laser power meter reads 1.300 watts and then after around 15 to 20 seconds it starts to drop very rapidly and at 50 to 60 seconds it by around dropped by half and yet nothing is warm to the touch, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results. and the whole time nothing is even warn to the touch ?
 
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diachi

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Why did you start a new thread for this? It's the exact same discussion you were having in the other thread...
 

Accutronitis

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Why did you start a new thread for this? It's the exact same discussion you were having in the other thread...
It's not the same discussion because I've eliminated everything except the driver (and maybe the diode but I don't thing it could be that) and what I am asking for in this thread is confirmation from people with experience with this issue.....

Any thoughts about this ?
 
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WizardG

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A PIR temp gun is not a laser power meter. For what you're doing, relative power measurements, a well heat-sinked solar cell would be more reliable.
 

Accutronitis

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A PIR temp gun is not a laser power meter. For what you're doing, relative power measurements, a well heat-sinked solar cell would be more reliable.
Forget what I said about a ir temp gun, Let try this, For about 15 to 20 seconds the Laser B laser power meter reads 1.300 watts and then after around 15 to 20 seconds it starts to drop very rapidly and at 50 to 60 seconds it by around dropped by half and yet nothing is warm to the touch, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results. and the whole time nothing is even warn to the touch ?

Could a diode be the cause or is it almost certainly a driver issue ?
 
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diachi

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Forget what I said about a ir temp gun, Let try this, For about 15 to 20 seconds the Laser B laser power meter reads 1.300 watts and then after around 15 to 20 seconds it starts to drop very rapidly and at 50 to 60 seconds it by around dropped by half and yet nothing is warm to the touch, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results. and the whole time nothing is even warn to the touch ?

Could a diode be the cause or is it almost certainly a driver issue ?

Is your diode pressed into the module all the way so that it's making good contact with the module and heatsink?

If you've verified the batteries are good (Have you hooked up to a bench PSU to see if the issue remains?) then that leaves either the diode or driver. Best/easiest way to verify then is to swap the driver or swap the diode to see if that eliminates the issue.
 

Accutronitis

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Is your diode pressed into the module all the way so that it's making good contact with the module and heatsink?

If you've verified the batteries are good (Have you hooked up to a bench PSU to see if the issue remains?) then that leaves either the diode or driver. Best/easiest way to verify then is to swap the driver or swap the diode to see if that eliminates the issue.
I'll know that a little later today, Could that cause the issue I described ?
 

Cyparagon

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This is ridiculous. Do you chop your vegetables with a mop, too?

An IR temp gun measures the IR emitted from surfaces. In most of them, the lens does not pass visible light in the first place. You'll end up heating the lens and the housing. As the housing temp increases, the ambient temp compensation will be screwed up and would explain a drop.

Don't use a thermometer as a power meter. It doesn't work, and you're proof of that.
 

Accutronitis

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This is ridiculous. Do you chop your vegetables with a mop, too?

An IR temp gun measures the IR emitted from surfaces. In most of them, the lens does not pass visible light in the first place. You'll end up heating the lens and the housing. As the housing temp increases, the ambient temp compensation will be screwed up and would explain a drop.

Don't use a thermometer as a power meter. It doesn't work, and you're proof of that.
Thanks for your opinion but I don't feel like arguing with anyone over this, That's not the only way I know what's it's doing ! for one thing I have eyes and I can see that it starts fine but very quickly I can see some diming, And it will burn very strong but between 20 to 40 seconds it's power to burn or melt has gone way down ! SO this statement is accurate....

laser power starts at 1.300 watts and then after around 15 to 20 seconds it starts to drop very rapidly and at 50 to 60 seconds it by around dropped by half and yet nothing is warm to the touch, A few minuets later I repeat the test with the same batteries and I get the same results
If you don't want to follow my premise and just ignore how in the hell I know what the laser is doing that's fine.

Please just go away..... Oh and take your insults with you !
 
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lasersbee

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Thanks for your opinion but I don't feel like arguing with anyone over this, That's not the only way I know what's it's doing ! for one thing I have eyes and I can see that it starts fine but very quickly I can see some diming, And it will burn very strong but between 20 to 40 seconds it's power to burn or melt has gone way down ! SO this statement is accurate....

If you don't want to follow my premise and just ignore how in the hell I know what the laser is doing that's fine.

Please just go away..... Oh and take your insults with you !
Every one here has the right to respond to your questions
in the way they please... You are on a public Forum. If you
don't want to hear any answers then don't ask questions.

Cyp is correct in stating that an IR temperature gun is not
a Laser Power Meter or was it designed to be one. It is a
non-contact thermometer and the way you are using it
only screams that you may have overheated the IR sensor
and it changes output.
It is like trying to cut vegetables with a mop. A mop was
not designed to cut vegetables..

You also stated that you repeated the same tests multiple
times with the same batteries without recharging.
Forget what I said about a ir temp gun, Let try this, For about 15 to 20 seconds the Laser B laser power meter reads 1.300 watts and then after around 15 to 20 seconds it starts to drop very rapidly and at 50 to 60 seconds it by around dropped by half and yet nothing is warm to the touch, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results, A few minuets later I repeat the test with the same batteries and I get the same results. and the whole time nothing is even warn to the touch ?

Could a diode be the cause or is it almost certainly a driver issue ?
1) can the batteries that you are using sustain the load
required by your laser over an extended period of time ??

2) have you recorded the voltage and current going to
your Laser during your tests ??

3) what current is your driver set at and which driver is it ??

4) Do you have a calibrated working Laser Power Meter ??


Jerry
 
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Accutronitis

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I just ran a test with the ir gun reading the surface of a black sheet of paper and on the other side of the sheet of paper I have the unfocused laser light, [Start test] the temp shoots way up very quickly and stabilizes within 5 seconds and holds steady for 20 seconds and then starts to drop some what quickly until 60 seconds goes by and I stop the test with the temp being almost half of what it was at the start !!!

I know what the output is doing ! My only question is with the symptoms of a laser that holds steady for about 20 and then rapidly drops in power output until it's around half the power at 60 second into the test and the test is stopped, Now all I what to know is could this possibly be a diode issue or is it almost certainly a driver issue ???
 

Accutronitis

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1) can the batteries that you are using sustain the load
required by your laser over an extended period of time ?? Yes

2) have you recorded the voltage and current going to
your Laser during your tests ?? voltage yes current no

3) Do you have a calibrated working Laser Power Meter ?? I think you already know I don't or why would I be testing it the way I am ?

4) what current is your driver set at and which driver is it ?? This is the driver....


 

lasersbee

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1) can the batteries that you are using sustain the load
required by your laser over an extended period of time ?? Yes

2) have you recorded the voltage and current going to
your Laser during your tests ?? voltage yes current no

3) Do you have a calibrated working Laser Power Meter ?? I think you already know I don't or why would I be testing it the way I am ?

4) what current is your driver set at and which driver is it ?? This is the driver....
1) what are the voltage readings over time ??
2) What are the voltage readings before and after the temp drops ??
2a) what are the current readings before and after the temp drops ??
3) you stated that you had a Laser B LPM....

Forget what I said about a ir temp gun, Let try this, For about 15 to 20 seconds the Laser B laser power meter reads 1.300 watts
Now it seems you are making up data... Really difficult to
work with erroneous data....

4) What is the driver current set to ??
It seems there are no wires on your driver...


Jerry
 
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