Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Science & Lasers



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 06-13-2008, 01:51 AM #1
VW's Avatar
VW VW is offline
Class 2M Laser
 
Join Date: Mar 2008
Posts: 579
Rep Power: 12
VW will become famous soon enough
VW VW is offline
Class 2M Laser
VW's Avatar
 
Join Date: Mar 2008
Posts: 579
Rep Power: 12
VW will become famous soon enough
Default Mathamatically working out average power over time

I was wondering, how do you mathamatically work out the average power of a laser over a set period of time? *I noticed a lot of people seem to base an average on the point where a laser rests for the longest. *That's all fine and well if the laser holds an average long enough for you to be able to determine it off hand. *But what about more unstable lasers? *For example and primarally, while read on a thermal unit my Spartan BP climbs slowly and drops slowly, so it never holds an average long enough to say, "that is the average." *What would be the method to record and work out the mathamatical average power over a set period of time? *


__________________
Dragon Lasers Hulk >150mW 532nm - Average 212mW
Dragon Lasers Spartan BP >40mW 473nm - Average 47mW
Kryton Groove PHR 405nm - TBC
VW is offline   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 06-13-2008, 01:58 AM #2
FrothyChimp's Avatar
Class 2M Laser
 
Join Date: Sep 2007
Posts: 977
Rep Power: 80
FrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond repute
FrothyChimp FrothyChimp is offline
Class 2M Laser
FrothyChimp's Avatar
 
Join Date: Sep 2007
Posts: 977
Rep Power: 80
FrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond repute
Default Re: Mathamatically working out average power over

Statistical analysis. Select a sample to use such as the measurement at >15 minutes or whatever the warmup time is for the laser. Take samples. Use that population in the arithmetic mean function. Your sample can really be anywhere on the curve or all of the curve but for average power you should use the output after warmup.

I should point out that statistical mean reports central tendency so using results from startup which often include the peak output can skew the average and should be considered before blindly using all data points.

Modify once again: I almost forgot there are ways to determine if data points are truly representative of a population by measuring standard deviation and setting what is called an alpha which is the point where the data value is rejected as not being part of the population sample. This helps eliminate those sometimes weird fluctuations and bring the average closer to the actual average.
__________________
The Frothy Chimp
Cynic Extraordinaire
Why yes, I am a rocket scientist

Good whiskey, fine cigars, long legged women and blues guitar.
That's what I like.

The strong shall stand, the weak shall fall by the wayside.
FrothyChimp is offline   Reply With Quote
Old 06-13-2008, 02:06 AM #3
VW's Avatar
VW VW is offline
Class 2M Laser
 
Join Date: Mar 2008
Posts: 579
Rep Power: 12
VW will become famous soon enough
VW VW is offline
Class 2M Laser
VW's Avatar
 
Join Date: Mar 2008
Posts: 579
Rep Power: 12
VW will become famous soon enough
Default Re: Mathamatically working out average power over

Thanks for the fast reply. Cool, I remember the idea of calculating the mean, but I've forgotten how to work it out. From what I can remember you would need to mark down the power at set intervals over a given length of time (say a minute), but I can't remember how to set up the numbers to get the exact mean (or as close to).
__________________
Dragon Lasers Hulk >150mW 532nm - Average 212mW
Dragon Lasers Spartan BP >40mW 473nm - Average 47mW
Kryton Groove PHR 405nm - TBC
VW is offline   Reply With Quote
Old 06-13-2008, 02:13 AM #4
FrothyChimp's Avatar
Class 2M Laser
 
Join Date: Sep 2007
Posts: 977
Rep Power: 80
FrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond repute
FrothyChimp FrothyChimp is offline
Class 2M Laser
FrothyChimp's Avatar
 
Join Date: Sep 2007
Posts: 977
Rep Power: 80
FrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond repute
Default Re: Mathamatically working out average power over

I believe you can enter the data points into excel and it will calculate mean and deviation for you. You can also simplify your rough data by using moving averages or even linear regression to better visualize what is happening inside the measurements.

Mean = add up all your data points and divide by the number of samples. But you have to be sure the data points are representing the most stable portion of the output. This can be an educated guess based on experience but if you are not sure you should use deviation and some other analysis to determine what should be included in the population for the average.

Modify: Now you have me on a statistical roll. One cool thing is you can use that average as the central point of a normal distribution and plot data points that go above that average and data points that go below that average. Find the range of a single standard deviation and you can calculate whether the power stability advertised is what you are getting.
__________________
The Frothy Chimp
Cynic Extraordinaire
Why yes, I am a rocket scientist

Good whiskey, fine cigars, long legged women and blues guitar.
That's what I like.

The strong shall stand, the weak shall fall by the wayside.
FrothyChimp is offline   Reply With Quote
Old 06-13-2008, 01:10 PM #5
VW's Avatar
VW VW is offline
Class 2M Laser
 
Join Date: Mar 2008
Posts: 579
Rep Power: 12
VW will become famous soon enough
VW VW is offline
Class 2M Laser
VW's Avatar
 
Join Date: Mar 2008
Posts: 579
Rep Power: 12
VW will become famous soon enough
Default Re: Mathamatically working out average power over

Awesome man, thanks. Deffinately re-jogged my memory. The laser I need this for reads pretty stable anyway on a thermal unit, it's always concistant in the speed of it's power climb and drop, so marking accurate data points shouldn't be too hard.

If I'm wanting an average over a period of time, I would need to mark down it's power, would you say, every 5 seconds or so?
__________________
Dragon Lasers Hulk >150mW 532nm - Average 212mW
Dragon Lasers Spartan BP >40mW 473nm - Average 47mW
Kryton Groove PHR 405nm - TBC
VW is offline   Reply With Quote
Old 06-13-2008, 01:19 PM #6
FrothyChimp's Avatar
Class 2M Laser
 
Join Date: Sep 2007
Posts: 977
Rep Power: 80
FrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond repute
FrothyChimp FrothyChimp is offline
Class 2M Laser
FrothyChimp's Avatar
 
Join Date: Sep 2007
Posts: 977
Rep Power: 80
FrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond reputeFrothyChimp has a reputation beyond repute
Default Re: Mathamatically working out average power over

Yes, every 5 seconds will work if the unit is fairly stable. That's the magic and the horror of statistics. Sample to little and you may miss important swings in the curve. Sample too much and your math can become too unwieldy or you have to justify throwing out data points.
__________________
The Frothy Chimp
Cynic Extraordinaire
Why yes, I am a rocket scientist

Good whiskey, fine cigars, long legged women and blues guitar.
That's what I like.

The strong shall stand, the weak shall fall by the wayside.
FrothyChimp is offline   Reply With Quote
Old 06-13-2008, 02:01 PM #7
VW's Avatar
VW VW is offline
Class 2M Laser
 
Join Date: Mar 2008
Posts: 579
Rep Power: 12
VW will become famous soon enough
VW VW is offline
Class 2M Laser
VW's Avatar
 
Join Date: Mar 2008
Posts: 579
Rep Power: 12
VW will become famous soon enough
Default Re: Mathamatically working out average power over

Okay cool man, thanks.
__________________
Dragon Lasers Hulk >150mW 532nm - Average 212mW
Dragon Lasers Spartan BP >40mW 473nm - Average 47mW
Kryton Groove PHR 405nm - TBC
VW is offline   Reply With Quote
Old 06-14-2008, 10:48 PM #8
Junior Member
 
Join Date: May 2008
Posts: 22
Rep Power: 0
NovoRei is on a distinguished road
NovoRei NovoRei is offline
Junior Member
 
Join Date: May 2008
Posts: 22
Rep Power: 0
NovoRei is on a distinguished road
Default Re: Mathamatically working out average power over

You could take a 2 minutes, 5-5secs, then apply the mean theorem. The area below the graph divided by the lenght will give the mean power.

Linear regression then derivation can be done too.


Ah, and cut the first 5 seconds.
NovoRei is offline   Reply With Quote
Old 06-15-2008, 02:16 AM #9
Hemlock_Mike's Avatar
Class 4 Laser
 
Join Date: Jan 2007
Location: North Iowa
Posts: 6,187
Rep Power: 4528
Hemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond repute
Hemlock_Mike Hemlock_Mike is online now
Class 4 Laser
Hemlock_Mike's Avatar
 
Join Date: Jan 2007
Location: North Iowa
Posts: 6,187
Rep Power: 4528
Hemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond reputeHemlock_Mike has a reputation beyond repute
Default Re: Mathamatically working out average power over

Frothy --

Thanks for reminding me why I hated Stat 101 ;D

Mike
__________________
It's a dog's life
Hemlock_Mike is online now   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 05:09 PM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC