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What if I Don't Have an LPM?

daguin

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The question comes up fairly regularly asking how one can estimate the output (mW) of a laser based on comparing it to other lasers or by what it can burn

Unfortunately, what it "looks like" to you (or anyone else) or how well it burns something is almost meaningless

How may mW would you estimate this laser to be


How about this one?


No -- wait. It's a trick question. They are both the same laser
Wider beams "look" brighter
Thinner beams burn better
A focusable laser burns better than one that is focused to "infinity"
Beams appear brighter if there is a lot of moisture (humidity) or "smoke" or dust in the air
The "steadiness" of your hand and the color of the target greatly affect burning

One CANNOT "estimate" the output of as laser by visual ques or how it burns stuff

How powerful is the laser lighting this match?


How about 35mW?
That video is in real time
The match ignites almost instantly

Get the laser measured by an LPM
It is the ONLY way to be able to say what the output is

Peace,
dave
 
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Blord

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That should nail the problem. The only way to determine the output is measuring by a proper LPM.
 
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Fortunately, there's a thread to go to, should someone want to find another member near them, who has an LPM.
 

daguin

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Very helpful vid from styro

I would still posit that ALL of the above warnings and qualifiers still apply

If the 35mW laser is focused better than the 100mW laser, the 35mW laser will burn better and faster than the 100mW

My video above shows a well focused 35mW laser igniting a match MUCH faster than his 100mW laser

Peace,
dave
 

TheDukeAnumber1

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The big issue is it's really difficult to let go of a precious build, I know because I've struggled with this, and send it off to someone you've never met to have it metered. At the same point it's a steep price to buy your own to know the exact mW when a lot of threads have good info on what your ballpark output is at measured currents, especially if your not a fan of the calibrated thermo sensors and want an Ophir.
 

ARG

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Good thread Dave!

It's also hard to tell the power by burning things since objects will absorb each wavelength with differing effects.
 
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daguin

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The big issue is it's really difficult to let go of a precious build, I know because I've struggled with this, and send it off to someone you've never met to have it metered. At the same point it's a steep price to buy your own to know the exact mW when a lot of threads have good info on what your ballpark output is at measured currents, especially if your not a fan of the calibrated thermo sensors and want an Ophir.
We know "why" people want to estimate without an LPM
The point here is that it cannot be done with any degree of certainty

Peace,
dave

**EDIT** -- I'll sell you a 20W Scientech LPM with a 10W thermopile calorimeter for $300, plus shipping
 
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TheDukeAnumber1

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**EDIT** -- I'll sell you a 20W Scientech LPM with a 10W thermopile calorimeter for $300, plus shipping
Someday yes I'll invest, but not today :) Good thread though, should be included in reading material for newcomers. If beam power density was easier to obtain w/o an LPM I'd imagine there would be less confusion.

Peace,
Kyle
 

Gun

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Good thread. I'm not sure if I should make a serperate thread for this or not, but what is the most "bang for buck" LPM. Nothing expensive, just the cheapest LPM that still mantains reasonable quality :)
 

hwang21

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Maybe a bluefan LPM? There's no LPM that's very cheap haha otherwise there wouldn't be a problem with people guesstimating their lasers' output power :p
 

daguin

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Good thread. I'm not sure if I should make a serperate thread for this or not, but what is the most "bang for buck" LPM. Nothing expensive, just the cheapest LPM that still mantains reasonable quality :)
That depends on what your needs are

Peace,
dave
 

lasersbee

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This Post has been Censored by lasersbee

Just doing some of my own CENSORING....


Jerry
 
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Pman

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Couldn't agree more. It's why it started driving me nuts not knowing true outputs including the dreaded IR content and also why I have a TEC still in case something happens to my Ophir.
 




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