Necessary for a laser store to have a LPM?

[BKarim]

yes tech_junkie is very technical.
just remember this:

checking quality is easy: point the laser to a small black disk on a white surface.
a good laser will throw one (and not two) small point on the black disk and very little parasite light on the white surface (maybe even no parasite light at all).
also if the point is too big, the laser has a bad divergence

 

[John7788]

yes tech_junkie is very technical.
just remember this:

checking quality is easy: point the laser to a small black disk on a white surface.
a good laser will throw one (and not two) small point on the black disk and very little parasite light on the white surface (maybe even no parasite light at all).
also if the point is too big, the laser has a bad divergence

OK, will do the same, thanks !

 

[DJNY]

Please test this laser at first!
600mW Open-Back Focal Adjust Blue Violet Laser Pointer Set(2*16340 Included) $226.19 Free Shipping

 

[Xplorer877]

LOL, What answer did you really expect? It's common sense if it's your desire to become reputable on the forums.

But as to all the other wholesale Chinese distributors... It's a a marketing ploy, and 95% of their sales are to people who will never be able to check or know the difference.

It's the same marketing ploy Stun Gun manufacturers use. There is no way in hell that a handheld device running off a 9v battery will generate half a million volts.

-Tony

 

[HIMNL9]

..... There is no way in hell that a handheld device running off a 9v battery will generate half a million volts .....

Oh, no, for this, there is a way ..... using a custom made transformer with "100.000 to 1" turns proportion with 0,001mm dia wire, you can easily reach also one million volts ..... at approximatively 1 or 2 nanoAmpere current (and also, don't ask how much it cost you the transformer )

(sorry, just can't resist)

 

[John7788]

Oh, no, for this, there is a way ..... using a custom made transformer with "100.000 to 1" turns proportion with 0,001mm dia wire, you can easily reach also one million volts ..... at approximatively 1 or 2 nanoAmpere current (and also, don't ask how much it cost you the transformer )

(sorry, just can't resist)

:beer::beer::beer:

 

[Xplorer877]

Theoretically it is possible.
Once I saw a 200kv mini marx generator that could make 18in arcs with a 9v! That was cool!

-Tony

 

[Vega]

I like this thread, pretty good questions that clarified some doubts I have had myself!
on the testing quality of the laser beam with the small black disk... how big should the black disk be?
and will a small round black paper circle cut out work? on top of a white sheet of paper?
I tired it this way and my personal laser showed one small round circle of light does that mean its pretty decent?

 

[HIMNL9]

The "black dot" is for reduce the reflections that can saturate your eyes (or any camera you are trying to use), so it permit you to see the "surrounding" of the dot, for check for "splashes" and other artifacts .....

I think that my system is also better , if you have the possibility to make precise holes in a paper sheet, or also better, in a thin sheet of white cardboard (just cause it's more rigid) ..... make precise holes of, say, 1mm, 1,5mm, 2mm, and so on, til 5mm, at a certain distance one from the other (say, left around them at least 10cm or similar) ..... so, when you point the beam exactly at the hole, when you pass it in the hole that don't give you any reflection of the main beam on any borders, you can see clearly all the surrounding of the beam (i use this system, and have seen it also eliminate all the reflections from the black dot or disk, that for high powers are still enough for disturb your vision, and that permit you also to check focused or "burning" beams, that otherwise may burn the black disk)

EDIT: as suggestion, for make precise holes in thin cardboard, without punchers, you can place the point that you want to drill between two pieces of hard plastic or metal, well pressed ..... this way, also with drill bits, the holes are usually decently good

 

[John7788]

The "black dot" is for reduce the reflections that can saturate your eyes (or any camera you are trying to use), so it permit you to see the "surrounding" of the dot, for check for "splashes" and other artifacts .....

I think that my system is also better , if you have the possibility to make precise holes in a paper sheet, or also better, in a thin sheet of white cardboard (just cause it's more rigid) ..... make precise holes of, say, 1mm, 1,5mm, 2mm, and so on, til 5mm, at a certain distance one from the other (say, left around them at least 10cm or similar) ..... so, when you point the beam exactly at the hole, when you pass it in the hole that don't give you any reflection of the main beam on any borders, you can see clearly all the surrounding of the beam (i use this system, and have seen it also eliminate all the reflections from the black dot or disk, that for high powers are still enough for disturb your vision, and that permit you also to check focused or "burning" beams, that otherwise may burn the black disk)

EDIT: as suggestion, for make precise holes in thin cardboard, without punchers, you can place the point that you want to drill between two pieces of hard plastic or metal, well pressed ..... this way, also with drill bits, the holes are usually decently good

good points!

BTW,HIMNL9, how long have you been researching lasers? I hope one day I can be as professional as you.

 

[HIMNL9]

Well, i'm not a laser expert, but i'm in the field of electronic (and lasers) as hobbyst, from 1977, and also worked for almost 21 years as "prototyper" (or, any way you call someone that design, build and test new electronic circuits) ..... i know, i know, i'm old ..... and i'm a damn curious, too, so all the times i see something that interest me, i always try to learn all the possible .....