Laser question

[AK]

Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

 

[George Herold]

On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:

Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

 

[John Larkin]

On Tue, 30 Apr 2019 06:12:12 -0700 (PDT), AK
<scientist77017@gmail.com> wrote:

Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A resistor at minimum, preferably a real current source. Laser diodes
can be operated constant-voltage, but the voltage has to be just
right. You could experiment carefully with an adjustable power supply.
Or just dump in 20 mA and be safe.

It's possible that the laser module has a built-in resistor or current
limiter. Experiment.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

On Tuesday, April 30, 2019 at 11:29:22 PM UTC+10, George Herold wrote:

On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.

Laser diodes do have a nasty habit of blowing up if maximum current is exceeded, even very briefly.

The active junction is remarkably small, and heats up correspondingly fast.

Can't remember when I first heard that - probably back in 1992. Heard it early enough that I didn't ever manage to test it, so I can't guarantee that it is true.

--
Bill Sloman, Sydney

 

[Jeff Liebermann]

On Tue, 30 Apr 2019 06:12:12 -0700 (PDT), AK
<scientist77017@gmail.com> wrote:

Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

When in doubt, search what others have done to power their lasers:
<https://www.google.com/search?q=laser+diode+power+supply+schematic&tbm=isch>
<https://www.repairfaq.org/sam/laserdps.htm#dpstoc>
Kinda looks like all are current driven, not voltage.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Martin Brown]

On 30/04/2019 15:02, bill.sloman@ieee.org wrote:

On Tuesday, April 30, 2019 at 11:29:22 PM UTC+10, George Herold
wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply
the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW Working
current: Min 10mA, Typical 20mA, Max 25mA Working voltage: Min
2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.

Laser diodes do have a nasty habit of blowing up if maximum current
is exceeded, even very briefly.

If in doubt a series resistor with the voltage supply to make sure it
can't reach the absolute maximum current rating of the device.

The active junction is remarkably small, and heats up correspondingly
fast.

Can't remember when I first heard that - probably back in 1992. Heard
it early enough that I didn't ever manage to test it, so I can't
guarantee that it is true.

I have retired the odd one by accident. Bare laser diodes need constant
current drive if they are to survive longer term. This sounds like a
module that contains a suitable driver and will work on 2-8v nominal.

The constant current might just be provided by a cheap resistor which
could mean that it gets a bit warm on >6v. They are definitely a lot
more tetchy than LEDs about this sort of thing.

--
Regards,
Martin Brown

 

[AK]

On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:

On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

 

[AK]

On Tuesday, April 30, 2019 at 10:19:39 AM UTC-5, Martin Brown wrote:

On 30/04/2019 15:02, bill.sloman@ieee.org wrote:
On Tuesday, April 30, 2019 at 11:29:22 PM UTC+10, George Herold
wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply
the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW Working
current: Min 10mA, Typical 20mA, Max 25mA Working voltage: Min
2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.

Laser diodes do have a nasty habit of blowing up if maximum current
is exceeded, even very briefly.

If in doubt a series resistor with the voltage supply to make sure it
can't reach the absolute maximum current rating of the device.

The active junction is remarkably small, and heats up correspondingly
fast.

Can't remember when I first heard that - probably back in 1992. Heard
it early enough that I didn't ever manage to test it, so I can't
guarantee that it is true.

I have retired the odd one by accident. Bare laser diodes need constant
current drive if they are to survive longer term. This sounds like a
module that contains a suitable driver and will work on 2-8v nominal.

The constant current might just be provided by a cheap resistor which
could mean that it gets a bit warm on >6v. They are definitely a lot
more tetchy than LEDs about this sort of thing.

--
Regards,
Martin Brown

I will look for a heat sink that I can attach to it.

Andy

 

[George Herold]

On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:

On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

 

[Phil Hobbs]

On 4/30/19 9:12 AM, AK wrote:

Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

Hard to tell. Got a link?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

On 4/30/19 11:21 AM, AK wrote:

On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Well, for three bucks you can get a few to blow up and a few to use.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[AK]

On Tuesday, April 30, 2019 at 12:45:54 PM UTC-5, Phil Hobbs wrote:

On 4/30/19 11:21 AM, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Well, for three bucks you can get a few to blow up and a few to use.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Have a related ?.

Working on the power supply for the laser diode.

Using resistors, I used a 5 volt transformer and brought it down to 2.5 volt using some 1/2 watt and .25 watt resistors.

If the laser outputs 5 mW and .25 watts = 250 Mw, then am I o.k.?

Andy

 

[Clive Arthur]

> On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:

<snipped>

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Looks like this is the one the OP meant, though the data sheet doesn't
agree with the specs...

https://www.jameco.com/z/104990022-Seeed-Studios-5mW-Laser-Module-Emitter-Red-Dot-Adjustable-Lens_2217692.html

So the OP posts a link to the wrong device, and the supplier prints
different specs to that device's data sheet. I don't see this ending well.

Cheers
--
Clive

 

[AK]

On Tuesday, April 30, 2019 at 1:12:43 PM UTC-5, Clive Arthur wrote:

On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:

snipped

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Looks like this is the one the OP meant, though the data sheet doesn't
agree with the specs...

https://www.jameco.com/z/104990022-Seeed-Studios-5mW-Laser-Module-Emitter-Red-Dot-Adjustable-Lens_2217692.html

So the OP posts a link to the wrong device, and the supplier prints
different specs to that device's data sheet. I don't see this ending well.

Cheers
--
Clive

No, this is what I will use as it is much cheaper than the adjustable one.

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

 

[George Herold]

On Tuesday, April 30, 2019 at 2:02:45 PM UTC-4, AK wrote:

On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Could you give some details on that?

Thanks,
Andy

googles, lm317 current source
http://www.bristolwatch.com/ccs/LM317.htm

GH
Not so good fro small currents but perfect for 10-100mA

 

[AK]

On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:

On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Could you give some details on that?

Thanks,
Andy

 

[AK]

On Tuesday, April 30, 2019 at 1:30:17 PM UTC-5, George Herold wrote:

On Tuesday, April 30, 2019 at 2:02:45 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Could you give some details on that?

Thanks,
Andy

googles, lm317 current source
http://www.bristolwatch.com/ccs/LM317.htm

GH
Not so good fro small currents but perfect for 10-100mA

+Vcc -------LM 317------10 ohm resistor-----lout
|
.1 uF capacitor

I have a 5 volt power transformer.

Do I get it down to 3 volts first?

Then connect positive to Vcc ?

Does the negative go straight to the laser diode while lout goes to the positive lead of the laser?

Andy

 

[AK]

On Tuesday, April 30, 2019 at 2:11:37 PM UTC-5, AK wrote:

On Tuesday, April 30, 2019 at 1:30:17 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 2:02:45 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Could you give some details on that?

Thanks,
Andy

googles, lm317 current source
http://www.bristolwatch.com/ccs/LM317.htm

GH
Not so good fro small currents but perfect for 10-100mA

+Vcc -------LM 317------10 ohm resistor-----lout
|
.1 uF capacitor

I have a 5 volt power transformer.

Do I get it down to 3 volts first?

Then connect positive to Vcc ?

Does the negative go straight to the laser diode while lout goes to the positive lead of the laser?

Andy

Thanks to everyone's help, I am learning even if it seems slow.

Andy

 

[George Herold]

On Tuesday, April 30, 2019 at 3:11:37 PM UTC-4, AK wrote:

On Tuesday, April 30, 2019 at 1:30:17 PM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 2:02:45 PM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 11:21:18 AM UTC-4, AK wrote:
On Tuesday, April 30, 2019 at 8:29:22 AM UTC-5, George Herold wrote:
On Tuesday, April 30, 2019 at 9:12:17 AM UTC-4, AK wrote:
Do I need anything to limit current to this laser or just supply the correct voltage?

5mW Laser Module Emitter - Red Dot Adjustable Lens
Specifications

Output Power: Min 2.5mW, Typical 3.0mW, Max 5.0mW
Working current: Min 10mA, Typical 20mA, Max 25mA
Working voltage: Min 2.3VDC, Typical 4.5VDC, Max 8.0VDC

Thanks.

A link would help. I'm guessing just the right voltage.
GH

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Could you give some details on that?

Thanks,
Andy

googles, lm317 current source
http://www.bristolwatch.com/ccs/LM317.htm

GH
Not so good fro small currents but perfect for 10-100mA

+Vcc -------LM 317------10 ohm resistor-----lout
|
.1 uF capacitor

I have a 5 volt power transformer.

Do I get it down to 3 volts first?

Then connect positive to Vcc ?

Does the negative go straight to the laser diode while lout goes to the positive lead of the laser?

Andy

Hmm, well definitely buy more than one laser diode...
'cause I'm guessing you will blow some.
You could put a few 1n4002 in series and use those for a dummy
laser diode.
Read that whole page on LM317 current sources... Make sure
you understand how to choose all the values.
(There is a connection from the output to the adjust pin of lm317)

Maybe read some about how the lm317 works.
10 ohms gives you 120 mA how much current do you want?

George H.

 

[AK]

On Tuesday, April 30, 2019 at 3:28:52 PM UTC-5, Martin Brown wrote:

On 30/04/2019 19:18, AK wrote:
On Tuesday, April 30, 2019 at 1:12:43 PM UTC-5, Clive Arthur wrote:
On Tuesday, April 30, 2019 at 11:56:27 AM UTC-5, George Herold wrote:

snipped

Ahh.. OK those specs look nothing like you first posted.
I would say that is a bare diode, and wants a current drive.
You can make one out of an LM317 and a resistor.

George H.

Looks like this is the one the OP meant, though the data sheet doesn't
agree with the specs...

https://www.jameco.com/z/104990022-Seeed-Studios-5mW-Laser-Module-Emitter-Red-Dot-Adjustable-Lens_2217692.html

So the OP posts a link to the wrong device, and the supplier prints
different specs to that device's data sheet. I don't see this ending well.

Cheers
--
Clive

No, this is what I will use as it is much cheaper than the adjustable one.

"https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2210204&productId=2210204"

That is a bare laser LED and needs something approximating a constant
current driver and a DC supply applied the right way round. I expect
laser diodes to be more tetchy than LEDs about reverse voltages too.

--
Regards,
Martin Brown

What do you think of this?

"https://www.amazon.com/Lights88-Laser-Module-Generator-Lasers/dp/B073P3FKVW/ref=sr_1_10?keywords=laser+diode&qid=1556656224&s=gateway&sr=8-10"

It has the driver. Should be all I need except for power source.

Andy