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

How to Register on LPF | LPF Donations

what laser is this??

Thepolnw

Thepolnw

0
Joined
Apr 8, 2011
Messages
21
Points
0
this is my old laser and couldn't figure the legs out so i try them all, and it didn't work:confused::confused:
i measured ohm and they all connected to each other
i open it up and got some pic for ya:undecided:
w7ls0y.jpg


30iuzgj.jpg


16hl16f.jpg

can u tell me which leg is - and +??:bowdown::bowdown:
 





It looks like it doesn't really matter any more.
The "try them all" approach have burned/melted the small wires that is supposed to connect the centre bit to the legs.

Can you tell if there have been a leg on the left, maybe broken off during dismantling?
 
no it's all like that when i open and it's doesn't look like anything has been broken away
i dont see any part of wire that should have left when it's burn out
(see with my microscope)

and my"try them all" i tried by using that thing that use to measure ohm
(idk what's it called)
b/c when i tried that with other laser, i will see little light on my cam

i mean u r pro have any ideas?
 
I have not seen that type before, and it looks broken to me.

What is the resistance between each leg?
Does your meter have a diode setting?
What colour was the laser?
 
Arggg:confused::confused:
it's ok now
i saw little metal thing on my laser and i try to pick it up and i broke the glass thingy by accident
:confused:
can u help me with my other laser?
10yfj3m.jpg

2dubc5d.jpg

my driver is 12.5-230 mA and 7.5-7.5 V
why my laser is not bright?
or that's the brightest it can be?
 
It looks like you have an IR diode, it does not get any brighter.
 
Yup i really think your flogging a dead horse on those diode. Get yourself a couple of LPC-815's or the like. Thier cheap as chips now.
 
Then you have a problem, this is a quite expensive hobby.

Also, when you write on a forum, you should take more care with your spelling.
People are less likely to respond to a poorly written post. I assume you have a full keyboard and are not using a phone?
 
I'm new here myself, so my response is worth every penny that you have paid for it.... and like Toke said, not much use now...
But, RE: the first LD that you butchered: I believe that you have an old low power RED with a photodiode monitor. Looking at the back, with the notch at the top, you have a pin at the top, 12 o'clock (pin1), then at 3 o'clock another pin connected to the case (pin2), and at 6 o'clock another pin (pin 3). Pin 1 could be LD+ (connected to the tall post in the pictures with a fine gold wire connected to the laser chip, which is bonded to the mass in the back of the picture (heat sinking block connected to the case of the LD and Pin 2, Common). Pin 2, as stated, is connected to the case and should be LD- and photodiode -. Pin 3 is connected to the short post in the picture and should be photodiode +. The photodiode is used to measure the light output of the laser and, through external circuitry, limit power to the LD. You either broke a connection in disassembly, burned a contact wire, or cracked the laser chip.
As stated, I could be way off, but it shure looks like the above is the case. Not many here on the forum seem interrested much in these LD's with photodiode monitors. Too low of a power capability, older technology (pd monitor not needed with more robust chips?), or no desire to add external circuits required to limit the LD. who knows... Anyway, it is an educational exhibit now.

Agree with Toke, the second LD looks like an IR. It's a BAD idea looking into the lense to see if it is on.
 
wow
oh i got it now
another question
how do i check that diode is burned or not?
what is the resistance should be when it's still good and burned?
and some laser diode look exactly the same but - and + might be different
how do i know that ,so i wont burn another one T_T
 
I wish someone like Toke, or daquin, would jump in on this one, But, Ibelieve,,,,
You need to use the lowest Ohm value if you have a selection on your dmm, the idea is low current. Higher range selection lets the meter supply more current. If it is auto ranging, I would suggest the Ohms setting, NOT the Diode Check setting as that usually reads in KOhms.

From what little I know on the subject, it appears that most all TO-5 cased LD's (5.56mm TO can case) share a common trait: looking at the back of the diode can, you will see two or three pins and a V notch. with the V notch at three o'clock, Pin 1 is at the top at 12 o'clock and is always positive, if it is a two pin case, it is likely an IR, the pin at the bottom is pin 2 and obviously negative. If it is a three pin case: the pin on the right at 3 o'clock is connected to the case ( for red LD's this is the negative pin, for blue it is not connected to the diode chip. The pin at the bottom at 6 0'clock is not connected or the photodiode monitor anode for red LD's, or the LD negative for Blues.
DMM set to ohms low scale, red lead on the posiitive pin (pin 1 at the top), black lead (common) connected to negative will read low ohms, connected to non-connected pin will read infinity, over range (usually a flashing one, "1"). Once you get a non over range reading, reverse the leads and you should get a High Ohms reading (this is where it may get dangerous for the LD (aside from the associated ESD problems) as your DMM might exceed the LD's max inverse voltage in trying to read the high resistance of the reverse biased diode, or you could also get avalanche current and damage the LD). Once you know what is + and what is -, hook up a variable current source starting at around 15-20 mA and SLOWLY crank up the current until you hopefully get a lase (instead of a smoke signal or cracked diode). This has worked for me without too much in blown diodes. DO NOT LOOK DIRECTLY INTO THE DIODE WINDOW TO DETERMINE IF IT IS GLOWING, let it shine on a piece of paper or something similar.
 
Last edited:
In order to identify a diode you have to know where it comes from, then you can check the relevant datasheet or forum post to seen the correct + and - pins.
You are going to need the datasheet anyway to know how many mA to give it.

To see if one is burned off you can try the diode check setting on your DMM.
It look a bit like ->I- and should give a result in volt.
 
line 13th ur infinity mean high ohm right?
thank you for info
i get it a lot now

my DMM dont have diode check, it the dial kind(needle pointing to number)
are there another way to check if it burned or not?

thank you very much
 
You must log in or register to reply here.


Back
Top