Laser safety

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  • #26
negitron
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Could I just slip in a terminal between 2 stacks of hte 2 batteries? Although this might be a problem since both lasers need to be controlled by 1 switch.circuit to see what I'm working with... Will the regulator be more efficient then a resistor?
Oh, and yes, this will work--just put the switch on the negative lead.
 
  • #27
Redbelly98
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A resistor could work, by acting as one half of a voltage divider (with the laser acting as the other), but this is horribly inefficient since any power not consumed by the laser will be dissipated through the resistor as waste heat, and inefficiency is not a good thing for battery operation.
Isn't the same true of a regulator, assuming we are talking about the linear type?

I do agree the regulator is a better choice than a resistor, though taking the 3V from half of the battery stack is more efficient and simpler as well.

Oh, and yes, this will work--just put the switch on the negative lead.
That was my first thought too. Alternatively, a double-pole switch could be used on the positive leads.
 
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  • #28
Andy Resnick
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Not for the ones the OP is dealing with--those are evidently diode lasers--actually, modules, complete with driving circuitry and collimating optics. In any case, most commercially-made laser systems have the high-voltage supply well insulated; cwertainly this is the case with smaller units typically available to hobbyists and such. The power supply for mine is entirely potted and fitted with Alden connectors to keep curious fingers from harm. Unless you chew through the cable, it's a practical impossibility to shock yourself with it.

In any event, I dispute your claim that electrical injuries are most common with respect to lasers in general and request you provide suitable documentation.
http://www.industrial-lasers.com/articles/article_display.html?id=330521 [Broken]
http://www.laserfx.com/BasicSafety/BasicSafety3.html
http://www.geocities.com/muldoon432/Non-Beam_Laser_Hazards.htm
http://www.uwm.edu/Dept/EHSRM/LAB/LaserSafety.html
http://jrm.phys.ksu.edu/Policy/esh.html
http://www.stanford.edu/dept/EHS/prod/researchlab/radlaser/laser/program/nonbeam_hazards.html
 
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  • #29
mgb_phys
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If the laser is only pulling 50mA then an AA will run it for about 80hours!

Black wire from the negative terminal of the first pair of batteries to a switch, then from other side of the switch two wires in parallel to the negative terminals of each laser.
Then a red wire from the positive terminal of the 3v laser to the positive terminal of the first battery pair and a red wire from the the positive terminal of the 6v laser to the positive terminal of the 2nd battery pair. Now just a wire from the positive terminal of the first battery pair to the negative terminal of the second pair.
You can either use two separate 2battery holders or make a connection to the mid-point of a 4battery holder.


(Sorry don't have a way of drawing on this machine)
 
  • #31
Redbelly98
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  • #32
Hey guys, i don't know much about lasers but i bought a laser pen overseas and my buddy told me it was too strong and could burn things. The sticker says class III, 100mW wavelength 650. Should I be concerned?
 
  • #33
mgb_phys
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The sticker says class III, 100mW wavelength 650. Should I be concerned?

Class IIIb
Lasers in this class may cause damage if the beam enters the eye directly. This generally applies to lasers powered from 5–500 mW. Lasers in this category can cause permanent eye damage with exposures of 1/100th of a second or less depending on the strength of the laser. A diffuse reflection is generally not hazardous but specular reflections can be just as dangerous as direct exposures. Protective eyewear is recommended when direct beam viewing of Class IIIb lasers may occur. Lasers at the high power end of this class may also present a fire hazard and can lightly burn skin.
So yes - be concerned
 
  • #34
Redbelly98
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Welcome to Physics Forums.

Yes, you should be very careful!

Legally, you can only buy 5 mW max in the U.S.

To burn things you'd probably need a lens to focus the beam to a smaller area, but yes it should be possible.
 

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