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 > Drivers, Test-load, Power Supply, & Batteries



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



Reply
 
LinkBack Thread Tools Display Modes
Old 06-09-2014, 08:26 PM #17
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 100w CW handheld laser?

Quote:
Originally Posted by deltawars View Post
I know we run them at Constant Current and the current should not be more then the rating, but is it fine if the voltage is around 2.6V even though the datasheet says 1.9v Max?

And sorry for asking all these questions but this isn't cheap, the 60w diode is 200 alone, plus cooling fans are like 30 each and I need 2-3 of them, then there is the battery which is like 60-70, and that is without the heat sinks, driver, protection, custom lens assembly and the host.
I understand its expensive thats why i'm saying run the diode at its recommended 42A , 1.8V Typical in CC mode as There is no way to answer the question ; it all depends on the current passing though the diode at 2.6 Volts

If its 42A at 2 Volts ( 1.8 V Typical ) , then it could be a lot higher at 2.6 V ( Quick guess looing at the other CCP diodes 60A + ) and that could cause thermal or optical damage .

The only way you would get 2.6 V across the diode is run it way above it's recommended current rating or from a voltage source , with again a current flow way above its rating .


__________________


Stuck In The places I Hated The Most , Reboot My Memory , Restart My heart , Seal Up All Of My Wounds Take Me Back To The Start !
Rip Me To Peices , Replace What You Can , Bury The Rest And Build A New Me To Plan !

Last edited by DashApple; 06-10-2014 at 01:05 PM.
DashApple is online now   Reply With Quote







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







Old 06-11-2014, 09:34 PM #18
deltawars's Avatar
Class 1M Laser
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
deltawars deltawars is offline
Class 1M Laser
deltawars's Avatar
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
Default Re: 100w CW handheld laser?

OK I finally bought a laser diode, it is only a 40W CW but I got a great deal, 17.89 + 25.93 Postage, $30.00 + $43.50 Postage.

Now I am trying to read some datasheets but I'm total confused on how to read these graphs, can someone please tell me.
Correct me if I am wrong but is this graph the forward voltage drop, if so why does the datasheet say Diode Forward Voltage 1.3 V TJ = 25C, IS = 59A, VGS = 0V?

__________________
Lasers aren't dangerous, only the people who use them are.

1mw 632.8nm Spectra Physics 156
3,000mw 445nm Stainless Steel
deltawars is offline   Reply With Quote
Old 06-12-2014, 12:04 AM #19
WizardG's Avatar
Class 2 Laser
 
Join Date: May 2011
Location: Oregon
Posts: 398
Rep Power: 2630
WizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond repute
WizardG WizardG is offline
Class 2 Laser
WizardG's Avatar
 
Join Date: May 2011
Location: Oregon
Posts: 398
Rep Power: 2630
WizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond reputeWizardG has a reputation beyond repute
Default Re: 100w CW handheld laser?

Quote:
Originally Posted by deltawars View Post
I know we run them at Constant Current and the current should not be more then the rating, but is it fine if the voltage is around 2.6V even though the datasheet says 1.9v Max?

And sorry for asking all these questions but this isn't cheap, the 60w diode is 200 alone, plus cooling fans are like 30 each and I need 2-3 of them, then there is the battery which is like 60-70, and that is without the heat sinks, driver, protection, custom lens assembly and the host.
That you even ask the first question above strongly suggests to me that your education and experience in electronics is inadequate for the project you're proposing. And you won't be able to cool the diode with a heatsink and a few fans. Liquid cooling (DI water or novec) is NOT optional.

The divergence of these large format 'bar' lasers is awful. If you want decent beam specs then your best bet would be to use one of these very high power 808 nm diode bars to pump an nd:yag rod.

I do wish you luck but I think the main product of your endeavors (whether successful or not) will be that you will learn a great deal. I think that in the long run you would be better off if you started with something a bit less ambitious like a 'from scratch' high-power DPSS green. That would teach you a lot about the care and feeding of high current diodes and the kind of optical systems you're going to need to collimate the output of a large diode bar.

Good luck, and remember your goggles!
__________________
125mW 405
1.157 watt 447
2 meter long hene @ 57mW
Assorted greenies, best @ 244mW of 520
WizardG is offline   Reply With Quote
Old 06-12-2014, 02:04 AM #20
Sigurthr's Avatar
Class 3B Laser
 
Join Date: Dec 2011
Location: Michigan's U.P.
Posts: 4,382
Rep Power: 873
Sigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond repute
Sigurthr Sigurthr is offline
Class 3B Laser
Sigurthr's Avatar
 
Join Date: Dec 2011
Location: Michigan's U.P.
Posts: 4,382
Rep Power: 873
Sigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond repute
Default Re: 100w CW handheld laser?

Quote:
Originally Posted by deltawars View Post
OK I finally bought a laser diode, it is only a 40W CW but I got a great deal, 17.89 + 25.93 Postage, $30.00 + $43.50 Postage.

Now I am trying to read some datasheets but I'm total confused on how to read these graphs, can someone please tell me.
Correct me if I am wrong but is this graph the forward voltage drop, if so why does the datasheet say Diode Forward Voltage 1.3 V TJ = 25C, IS = 59A, VGS = 0V?

Vsd (normally Vds) and reverse drain current should clue you in that this chart is for REVERSE BIAS tolerance; i.e. how it behaves when hooked up backwards. Also, Vgs on there suggests there is a Gate, a part of semiconductor architecture not present on diodes. Where did you get this chart from?
__________________
Amateur Multispectral Photographer - [X-Ray, UV, Vis, IR]
Amateur Electrical Engineer
Autodidact
Tesla Coil Expert

Last edited by Sigurthr; 06-12-2014 at 02:05 AM.
Sigurthr is offline   Reply With Quote
Old 06-12-2014, 02:09 AM #21
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Re: 100w CW handheld laser?

What's the link to where you bought the diode?
__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)

rhd is offline   Reply With Quote
Old 06-12-2014, 07:04 AM #22
deltawars's Avatar
Class 1M Laser
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
deltawars deltawars is offline
Class 1M Laser
deltawars's Avatar
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
Default Re: 100w CW handheld laser?

It is a n ch mosfet the part number is IRFP064N.
And woops wrong graph, i think im looking for the drain to source current and drain to source voltage, im trying to work out the forward voltage drop at 40-45A at the differnt temperatures, but im not sure on how the segments in the graph works.
__________________
Lasers aren't dangerous, only the people who use them are.

1mw 632.8nm Spectra Physics 156
3,000mw 445nm Stainless Steel
deltawars is offline   Reply With Quote
Old 06-12-2014, 10:59 AM #23
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 100w CW handheld laser?

What type of driver are you planning to use , linear or switching ?
__________________


Stuck In The places I Hated The Most , Reboot My Memory , Restart My heart , Seal Up All Of My Wounds Take Me Back To The Start !
Rip Me To Peices , Replace What You Can , Bury The Rest And Build A New Me To Plan !
DashApple is online now   Reply With Quote
Old 06-12-2014, 11:14 AM #24
deltawars's Avatar
Class 1M Laser
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
deltawars deltawars is offline
Class 1M Laser
deltawars's Avatar
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
Default Re: 100w CW handheld laser?

I just realized how the lines on the graph work.

Im 99% sure its linear im a small transistor a mosfet and 2 resistor, i have seen a few people use the same type of driver and it works very well.
__________________
Lasers aren't dangerous, only the people who use them are.

1mw 632.8nm Spectra Physics 156
3,000mw 445nm Stainless Steel
deltawars is offline   Reply With Quote
Old 06-12-2014, 01:03 PM #25
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 100w CW handheld laser?

Quote:
Originally Posted by deltawars View Post
I just realized how the lines on the graph work.

Im 99% sure its linear im a small transistor a mosfet and 2 resistor, i have seen a few people use the same type of driver and it works very well.
Well make sure you size the resistor correctly for the wattage and get a low tolerance one to stop current wander .
__________________


Stuck In The places I Hated The Most , Reboot My Memory , Restart My heart , Seal Up All Of My Wounds Take Me Back To The Start !
Rip Me To Peices , Replace What You Can , Bury The Rest And Build A New Me To Plan !
DashApple is online now   Reply With Quote
Old 06-12-2014, 02:51 PM #26
deltawars's Avatar
Class 1M Laser
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
deltawars deltawars is offline
Class 1M Laser
deltawars's Avatar
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
Default Re: 100w CW handheld laser?

I got a 100w 0.01ohm unfortunately the wattage going through it is 112W but its not going to be powered on for long anyway, I also have a 25C temp cutout for the mosfet, as the temperature of the mosfet rises so does the forward voltage drop which makes the current rise, I=Vds/R
__________________
Lasers aren't dangerous, only the people who use them are.

1mw 632.8nm Spectra Physics 156
3,000mw 445nm Stainless Steel
deltawars is offline   Reply With Quote
Old 06-12-2014, 02:58 PM #27
rhd's Avatar
rhd rhd is offline
Class 4 Laser
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
rhd rhd is offline
Class 4 Laser
rhd's Avatar
 
Join Date: Dec 2010
Posts: 8,491
Rep Power: 1392
rhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond reputerhd has a reputation beyond repute
Default Re: 100w CW handheld laser?

Quote:
Originally Posted by deltawars View Post
I got a 100w 0.01ohm unfortunately the wattage going through it is 112W but its not going to be powered on for long anyway, I also have a 25C temp cutout for the mosfet, as the temperature of the mosfet rises so does the forward voltage drop which makes the current rise, I=Vds/R
What ?!?

I don't know if you said anywhere what your LD's current is, but assuming it's roughly 40A (IRs are usually close to 1A / 1W output), then that's 40A running over your 0.01 ohm resistor.

P = I^2 x R = 40^2 x 0.01 = 1600 X 0.01 = 16W

Where are you getting 112W from?
__________________
CURRENT WAVELENGTHS:
405|441|450|467|473|495|505|520|532|556|PGLRG|589|594|632|638|660


SAFETY & IMPORTANT READING (threads authored and contributed to by various members of LPF):
- Federal Aviation Administration - Laser Safety Initiative (link)
- Info release from Laserglow - Default Canadian restrictions on portable lasers (link)
- The Necessity of Safety Goggles (link)

rhd is offline   Reply With Quote
Old 06-12-2014, 03:26 PM #28
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 100w CW handheld laser?

Based on 40A Setup

If you are using the circuit RHD posted the link to then the resistor you need is 0.0175 Ohms for 40A so power would be -

P = I^2 x R = 40^2 x 0.0175 = 1600 X 0.0175 = 28W

Mosfet Power dissipation =

Eg - 5 volt source , 2 volts over the diode at 40A , 0.7 volts over sense resistor and then 2.3 volts over the mosfet .

R = V/I = 2.3V/40A = 0.0575 Ohms .

P = I^2 x R = 40^2 x 0.0575 = 1600 X 0.0575 = 92W

Total power of circuit = 5*40 = 200W , 40W optical , 160W heat . ( Heat = 28W in resistor , 40W ish in diode , 92W in Mosfet , + 40W optical = 200W input as above )

Eff is around %20 based on input to optical over whole system


------------------------

That 0.01 ohm resistor you plan to use in the same circuit will cause a current to flow of 70A though that diode and it wont like it ...

P = I^2 x R = 70^2 x 0.0575 = 4900 X 0.01 = 49W

Mosfet = ( same 5V supply )

R = V/I = 2.3V/70A = 0.0328 Ohms

P = I^2 x R = 70^2 x 0.0328 = 4900 X 0.0328 = 160.72W
__________________


Stuck In The places I Hated The Most , Reboot My Memory , Restart My heart , Seal Up All Of My Wounds Take Me Back To The Start !
Rip Me To Peices , Replace What You Can , Bury The Rest And Build A New Me To Plan !

Last edited by DashApple; 06-12-2014 at 03:50 PM.
DashApple is online now   Reply With Quote
Old 06-12-2014, 04:41 PM #29
deltawars's Avatar
Class 1M Laser
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
deltawars deltawars is offline
Class 1M Laser
deltawars's Avatar
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
Default Re: 100w CW handheld laser?

Ahh Cr*p why do I never read anything properly.
__________________
Lasers aren't dangerous, only the people who use them are.

1mw 632.8nm Spectra Physics 156
3,000mw 445nm Stainless Steel

Last edited by deltawars; 06-12-2014 at 04:54 PM.
deltawars is offline   Reply With Quote
Old 06-12-2014, 05:58 PM #30
deltawars's Avatar
Class 1M Laser
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
deltawars deltawars is offline
Class 1M Laser
deltawars's Avatar
 
Join Date: Sep 2013
Location: Es*** UK
Posts: 167
Rep Power: 26
deltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond reputedeltawars has a reputation beyond repute
Default Re: 100w CW handheld laser?

OK after reading and learning some more, I'm getting confused and I want to ask some questions, sorry for my noobness but sometimes the internet is great, and sometimes there is a lot of contradictory information.

Correct me if I am wrong but,
to work out the value of the sensing resistor(Rs) I need 2 things
1.Forward Voltage drop of the diode in the mosfet.
2.The current I want.

The diode is Between Drain to Source right?
so to work out the voltage drop of the diode I need this graph?


So using a transistor at 7V and the mosfet at 25oC and the current at 40A the Forward voltage drop of the diode is about 0.37V?



I feel so stupid as this is basic stuff
__________________
Lasers aren't dangerous, only the people who use them are.

1mw 632.8nm Spectra Physics 156
3,000mw 445nm Stainless Steel

Last edited by deltawars; 06-12-2014 at 05:58 PM.
deltawars is offline   Reply With Quote
Old 06-12-2014, 06:19 PM #31
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Posts: 1,354
Rep Power: 6853
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 100w CW handheld laser?

No worries ,

The internal diode inside the mosfet plays no part in the circuit , its formed anti-parallel when the drain/source junction is made

All you need to mainly worry about is the resistor that sets the current .

As above for 40A you need 0.0175 Ohm resistor ,

The sense resistor is worked out as 0.7V ( transistor base/emitter drop ) devided by the current needed .

0.7V/40A = 0.0175 Ohms .

Voltage wise , there will be 0.7V over the sense resistor , around 2 volts over the laser diode and what's left will be over the mosfet , in the example I gave for a 5 volt supply there will be around 2.3 volts over the mosfet .

You have to remember the mosfet is being used as a variable resistor to control the current .

I can draw the circuit out with the basic relevant voltages on , resistor value if you like , I just need to know the supply voltage you intend to use and the current you would like to run the diode at and then I can work out power dissipation in mosfet and the resistor .
__________________


Stuck In The places I Hated The Most , Reboot My Memory , Restart My heart , Seal Up All Of My Wounds Take Me Back To The Start !
Rip Me To Peices , Replace What You Can , Bury The Rest And Build A New Me To Plan !

Last edited by DashApple; 06-12-2014 at 08:48 PM.
DashApple is online now   Reply With Quote
Old 06-13-2014, 02:59 AM #32
Sigurthr's Avatar
Class 3B Laser
 
Join Date: Dec 2011
Location: Michigan's U.P.
Posts: 4,382
Rep Power: 873
Sigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond repute
Sigurthr Sigurthr is offline
Class 3B Laser
Sigurthr's Avatar
 
Join Date: Dec 2011
Location: Michigan's U.P.
Posts: 4,382
Rep Power: 873
Sigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond reputeSigurthr has a reputation beyond repute
Default Re: 100w CW handheld laser?

Excellent work here, Twirly (ionlaser555)!

If he has already grabbed that 10mOhm resistor I recommend running a second one in series for 0.02 Ohms (~35A). Better to be a bit conservative anyway.

Oh, and 92W into a mosfet is nothing to scoff at, plan your thermal management!
__________________
Amateur Multispectral Photographer - [X-Ray, UV, Vis, IR]
Amateur Electrical Engineer
Autodidact
Tesla Coil Expert
Sigurthr is offline   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


LinkBacks (?)
LinkBack to this Thread: http://laserpointerforums.com/f67/100w-cw-handheld-laser-89683.html
Posted By For Type Date
Ghostbusters Proton Pack Gun images This thread Refback 04-28-2017 05:14 PM
Lipolbattery.com Traffic, Demographics and Competitors - Alexa This thread Refback 10-26-2016 07:36 AM










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 11:54 AM.


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