Green Lasers- Question about watts,amps,volts

This really doesnt have to be about green lasers only but i was wondering if someone could explain the differences between amps, watts, and volts and how they work in a laser(or any other device). Its been awhile since i took electronics and even then i barely understood the differences, they always used some analogy like a pipe and the water was electricity, the water pressure was volts, etc.
I know that by increasing the current you will also increase the watts, right? But then how do you increase the watts just by diode alignment?


Also how can i meausure the amps of my grean laser? i know i have a good DMM around somewhere but i dont knwo how to make it work for a laser and if i end up modding mine i dont want to blow it.

Thanks

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Uisgdlyast said:
Also how can i meausure the amps of my grean laser? i know i have a good DMM around somewhere but i dont knwo how to make it work for a laser and if i end up modding mine i dont want to blow it.

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-If you talk about measuring the optical power output, I can't help you since you must have a receptor associated with the DMM... and the formula to convert µA/mA of the receptor into optical mW

-If you talk about measuring the current consumption of a device, you have to 'cut' the original circuit to insert the DMM.

for example, the cap of the batteries removed :
[-] side of the device ---> [A/mA/red] side of the DMM
[-] side of the set of batteries ---> [COM/black] side of the DMM

The DMM set to Amps, and keep in mind that the fact of inserting the DMM in the circuit will modify a little the current consuption of the device ('cause the DMM is seen like a resistor by the rest of the circuit)
I mean that the current the DMM will give you (for example 310 mA) will not be exactly the current without it (say...315 MA for example)

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Uisgdlyast said:
if someone could explain the differences between amps, watts, and volts and how they work

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Volts are 'fixed' by the batteries (3V), Amps are determined by the device you power (say 300mA for a laser), Watts represent the power consumption of the device : 3V * 300mA == 900mW
so, say 900mW at 3V for a laser (5mW / 900mW leads to a 0.5% efficiency)
but this consumption can vary with the voltage applied by the batteries, for example if the laser is seen by the batteries like a resistor, you can have :
- 1.024W @ 3.2V
- 625mW @ 2.5 V

[ QUOTE ]
TTaz said:


-If you talk about measuring the current consumption of a device, you have to 'cut' the original circuit to insert the DMM.

for example, the cap of the batteries removed :
[-] side of the device ---> [A/mA/red] side of the DMM
[-] side of the set of batteries ---> [COM/black] side of the DMM

The DMM set to Amps, and keep in mind that the fact of inserting the DMM in the circuit will modify a little the current consuption of the device ('cause the DMM is seen like a resistor by the rest of the circuit)
I mean that the current the DMM will give you (for example 310 mA) will not be exactly the current without it (say...315 MA for example)

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Ok, I know I need to "cut" the circuit but I'm not exactly sure where to put the ends to measure and if i have to open it up, which i dont want to open it just yet. And if i do open it how would i go about connecting a power supply(my batteries) to it?


[ QUOTE ]
TTaz said:
Volts are 'fixed' by the batteries (3V), Amps are determined by the device you power (say 300mA for a laser), Watts represent the power consumption of the device : 3V * 300mA == 900mW
so, say 900mW at 3V for a laser (5mW / 900mW leads to a 0.5% efficiency)
but this consumption can vary with the voltage applied by the batteries, for example if the laser is seen by the batteries like a resistor, you can have :
- 1.024W @ 3.2V
- 625mW @ 2.5 V

[/ QUOTE ]

Thanks, I really just needed to know that watts are the consumption. If anyone wants to add more info to this feel free. Actually add as much as you like, I understand the basics of how they work. I'll try to read about it on my own though. Mostly how they relate together, I'm a little confused on how you can have a 3v source but change the amount of current(I'm actually good with this stuff too, i shoudl of paid more attention to the theory in electronics class)

thanks

you don't have to open the device, just remove the cap for the batteries (don't -yet- have a pointer, but I imagine that the case makes the [-] path for current)

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Uisgdlyast said:
I'm a little confused on how you can have a 3v source but change the amount of current

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take this smiley : /ubbthreads/images/graemlins/smoker5.gif there is a level difference between the reservoir and the ground (this is the 3V), you can adjust different diameters of tubing, there always will be the same 'potential difference' (the same hight), but the 'current' will be more important if the tubing is larger /ubbthreads/images/graemlins/wink.gif

ok, great. I actually love electronics but i'm a little behind on the theory.

Actually the casing provides the positive current? does it not?

Anyways i think i understand better how to do it now and i'm going to go try once i find my DMM in the mess i have

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Uisgdlyast said:
Actually the casing provides the positive current? does it not?

[/ QUOTE ]

In fact, I don't know how the batteries are to be placed.... [-] or [+] side at bottom...

Anyway... I'm in electronics since I have 8 years old (and I'm 25 now), so feel free to ask if you have any question on this vast subject /ubbthreads/images/graemlins/wink2.gif

If you wish to find the power output of your green laser, connect a single solar cell (the matte black type) to the meter, set it on low amps (the 1 amp or 2 amp scale), shine the laser at the solar cell, and use the following formula:

(current in amps as shown on the meter)*1239.7/532/0.97

If I remember correctly, the resulting value will be your laser pointer's power in watts. A final value of 0.04967 would equate to a laser power of just a tick under 50mW.

IMPORTANT: This mathematical formula will not work properly if you remove the IR filter from your green laser pointer. You will not get a correct measurement for the 532nm green laser line, and the formula is not correct for the 808nm and 1064nm laser lines that will be emitted by the laser with the IR filter removed either.

where can i get these solar cells?
I still would like to get a reading in mA but i cant figure out how to connect it together without opening it

Pictures worth a thousand.....

What kind of mw output are you getting off that 205 ma pointer?

On this particular pointer 23.3mW which is very good. This one cranked up in current would probably do somewhere in the 30mW to 40mW range from past experience.

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Uisgdlyast said:
where can i get these solar cells?

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I'm really not sure where you would be able to get one of these solar cells. I broke mine a couple of years ago, and do not yet have a replacement for it. /ubbthreads/images/graemlins/jpshakehead.gif

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Crosman451 said:
Pictures worth a thousand.....




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Thanks, i'm off to find my DMM now.

Also how much is a laser reading reading device like you have cost? it looks pretty small

Go to this link http://www.coherentinc.com/Products/index.cfm?fuseaction=Interfaces.Product&PCID=4&PLID=94&PDID=250

The Coherent LaserCheck power meter is one of the easiest to use meters out there. It is small like a oversized pen and can measure from 1mW to 1000mW. Ranges from 400nm to 1064nm. One of the most useful tools I've ever purchased.

You can also get them at Edmund Scientific.
http://www.edmundoptics.com/onlinecatalog/DisplayProduct.cfm?productid=1403
Expect to pay $310.00 for it.
I think you can measure 0.5µW (0.5 microwatts) to 1,000mW, at wavelengths of 400nm to 1,064nm.

Here is some of the equipment that I use for testing power and energy of lasers. Several detector heads are required for the different types of lasers and power outputs. The LM-1 head is very accurate for measuring up to 1000mW. The large round one is good for 100W! The Coherent Field Master GS has served me well for the last couple of years for various larger lasers. But for the money the small pen LaserCheck is so convienent it's hard to beat for the smaller lasers, especially pointers.

wow, crosman, i gotta ask what do you do for a living? or are lasers just a hobby?

At this point, just an "Expensive Hobby" /ubbthreads/images/graemlins/mecry.gif /ubbthreads/images/graemlins/mecry.gif /ubbthreads/images/graemlins/mecry.gif

It started with a lust for knowing just "what is the power output" of this laser. The LaserCheck is OK, but records a sampling of the lasers output. It checks for 2 seconds and locks in a reading. I wanted to read "real time", so the Field Master GS was the next logical step along with the different detector heads. This equipment was "necessary" for my mods. Ah, the thirst accurate knowledge, my weakness.
/ubbthreads/images/graemlins/help.gif /ubbthreads/images/graemlins/help.gif

/ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif

crap.. sounds like what would happen to me if i had more money.

Mind if i ask what kind of lasers(and how many) you own? I mean if you can measure 100W you gotta have something cool.

Also any tips on getting the greenies end cap off? must of spent an hour on it with a razor blade and all i got off was the paint /ubbthreads/images/graemlins/frown.gif

Several HeNe lasers of various powers, a few argons from 60 to over 200mW plus. Larger argons up to 3W and a white light system over 4W. Not to mention the green DPSS stuff, 20mW to 300mW. Red diodes of all sorts and a very unique violet 409nm pointer. All I'am admitting to, for now./ubbthreads/images/graemlins/sssh.gif

What kind of pointer do you have anyway? Leadlight or Changchun.