Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

My LD barely glows

S

sometoymachine

0
Joined
Dec 9, 2010
Messages
63
Points
0
I've tried to hook up a LD to a small DC wire from a PSU that generates only 3.4 volts. I assume it's relatively safe since it's a low voltage. When I plug it in and hit the switch though, it glows but not near as bright as it should. Surely I couldn't have LED'd my LD from that little power right ? This is the second diode I have had do this, however, I'm not sure what wrote speed the DVD-r I got it from was.

Be easy on me, it's my first time.
 





Xtrm2Rick

Xtrm2Rick

0
Joined
Oct 6, 2009
Messages
821
Points
18
what mAh rating does the psu deliver? also what diode?

if it was a loc red and the psu delivers like 800mah, it most probobly toasted your diode.

might also be a IR diode..

more info would be needed to help i gues
 
Grix

Grix

0
Joined
Dec 9, 2008
Messages
2,190
Points
63
LD's don't need regulated voltage, they need regulated current. You most likely blew your diode from overcurrent. Or the current/voltage might have been too low and not enough to get the diode lasing.
 
Leodahsan

Leodahsan

0
Joined
Aug 7, 2010
Messages
2,086
Points
0
Xtrm2Rick said:
what mAh rating does the psu deliver? also what diode?

if it was a loc red and the psu delivers like 800mah, it most probobly toasted your diode.

might also be a IR diode..

more info would be needed to help i gues
Click to expand...

mAh is a rating used for batteries (mili Ampères / Hour).. the rating used for PSUs is mA or A (miliampère or Ampére).

:)

oh thats a really tough diode shining at 3.3v @ 20amps.. he STILL shine some light?
 
Last edited:
Eudaimonium

Eudaimonium

0
Joined
Feb 5, 2008
Messages
6,252
Points
83
Xtrm2Rick said:
what mAh rating does the psu deliver? also what diode?

if it was a loc red and the psu delivers like 800mah, it most probobly toasted your diode.

might also be a IR diode..

more info would be needed to help i gues
Click to expand...
PSUs don't have capacity, batteries do.

mAh is unit of capacity, mA or A is unit of current. Don't mix those two, please :)

If battery says 2000mAh, it means that when drawing 2000mA out of it, it will last exactly one hour.

+3.3 V, 20A you say? Hahaha, I wonder if your diode is still in the solid out of 3 possible states. I'd guess gas by now.

You totally fried it.

Next time, do more research about regulated , that is, constant current source.
 
Eudaimonium

Eudaimonium

0
Joined
Feb 5, 2008
Messages
6,252
Points
83
About 40 times more than most powerful red diodes from DVD drives can handle for long life, yes.

Maximum would be 500mA, with exeptionally good heatsinking and stuff.

Don't go over 400mA.

600mA = Dead.
 
Eudaimonium

Eudaimonium

0
Joined
Feb 5, 2008
Messages
6,252
Points
83
I'm sorry, what "CCD" ? You mean, Constant Current Driver?

No, any circuit with constant current regulation will do fine, linear or switching drivers - does not matter, if it provides good current.

Problem is that your PSU has constant voltage source, and diode just pulled all the current it could. You need to regulate the current and let the diode take the voltage it can.

That's what the proper drivers are doing.
 
S

sometoymachine

0
Joined
Dec 9, 2010
Messages
63
Points
0
I'll have to make a driver then because the ones I bought are too small for my amateur hands to work with.

Thanks again for the help. If only I weren't at work, I would have asked prior.
 
Eudaimonium

Eudaimonium

0
Joined
Feb 5, 2008
Messages
6,252
Points
83
Here you can buy a wide range of stuff:
HighTechDealZ - High Tech DealZ

You can buy LPC-815 sled which has powerful red diode for $10.50. I suggest you pick up one PHR-803T also, it has 100mW violet bluray diode, it's really fun seeing that color :)
 
qumefox

qumefox

0
Joined
Mar 26, 2010
Messages
3,220
Points
0
20A? Wow. I'm surprised it even still emitted light at all. I figure you would have burned off the bonding wires at that current.
 
Xtrm2Rick

Xtrm2Rick

0
Joined
Oct 6, 2009
Messages
821
Points
18
ya you guys got me on the mah thing my mistake lol :p ofcourse i know the difference between mah and ma rating :p wasnt thinking clearly @ work.
some one kept asking me what i do with all those lasers.

and damn 20A, a wonder that the diode didnt give a "pop" :eek:
 
Last edited:
You must log in or register to reply here.




Top