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.

One laser store meets all your needs

 Laser Pointer Forums - Discuss Laser Pointers reference voltage

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

03-29-2009, 04:42 PM #1
 Junior Member Join Date: Jan 2009 Posts: 16 Rep Power: 0
chottu
Junior Member

Join Date: Jan 2009
Posts: 16
Rep Power: 0
reference voltage

ONe more annoying question .......

What the hell is ref voltage and why should it always be 1.25 ?

thanks.

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

03-29-2009, 04:54 PM #2
 Class 4 Laser Join Date: Sep 2007 Location: Northern CA, U.S. Astrophotography! (Some of my Photos) Posts: 9,851 Rep Power: 3922
jayrob
Class 4 Laser

Join Date: Sep 2007
Location: Northern CA, U.S. Astrophotography! (Some of my Photos)
Posts: 9,851
Rep Power: 3922
Re: reference voltage

That is what the regulated voltage is on the LM317. (between the sense pins)

It is actually a voltage regulator. We use it to regulate current, which it does by regulating the voltage very precisely to 1.25 volts.

To figure current...

1.25/ohms of resistance = current.

Example:

1.25/10 ohms = 125mA's
1.25/5 ohms = 250mA's

And so on...

The LM317 will take up to 37 volts supply. For a red build, you will want to supply the driver with more than 6 volts. Which is why you would use 2 X 3.6 volt batteries. Because 2 X 3.0 volt batteries will start to drop below 6 volts very soon. Then the LM317 will 'drop out' and not regulate the current.

For a blu-ray build using a DDL driver like this, you would want 9 to 12 volts supply...
Jay
__________________
Personal lasers:
(just a few - too many to list) RPL 425, Sypder III Krypton, RPL 35 (473), GLP-473, GLP-593.5, HeNe 632.8,
Many DIY 445, red, blu-ray, green, 635, and 450 builds...

Looking for a DIY kit?

Take a look at some of my more popular kits linked in color...

* FS: 405-G-1 Glass Lens Mod for Blu-ray! 31% increase in power vs AixiZ acrylic!

* FS: New! 1000 Lumen XML-2 Maglite Modification With Voltage Monitor! - Parts or Complete Light! Must see!

* FS: Polished Stainless Steel Green Kit! Easy assembly in minutes!

* FS: Large Maglite Monster Kits! Side Button Forward Clicky! Custom Head Option! Gnarly...

Click here for a list of my build kits! Projects and tutorials too!

03-29-2009, 04:59 PM #3
 Class 3B Laser Join Date: Jul 2007 Location: Berkshire UK Posts: 2,749 Rep Power: 193
rog8811
Class 3B Laser

Join Date: Jul 2007
Location: Berkshire UK
Posts: 2,749
Rep Power: 193
Re: reference voltage

On a need to know basis you don't need to know . All you need to do is measure it with a DVM. if it is 1.25v you circuit is working correctly.

If you realy cannot live without that piece of knowledge read the data sheet which was linked for you on another thread.

Regards rog8811
__________________
See all of my videos on Vimeo
http://www.vimeo.com/4454150

Lots of tutorials and information on lasers
http://www.rog8811.com/

In the land of the blind the one eyed man..... is most likely holding the laser

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

All times are GMT. The time now is 06:10 AM.

 -- DarkShadows V5 -- Responsive LPF -2562016 -- Default Style Contact Us - Laser Pointer Forums - Archive - Top