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

How to Register on LPF | LPF Donations

Please help, making a driver

Kakashi987

Kakashi987

0
Joined
Mar 2, 2010
Messages
42
Points
0
I'm looking for the capacitor in this diagram:
LM317%20components01.jpg


I found this 10µF 16V 20% Dipped Tantalum Capacitor - RadioShack.com

Is it the same thing?

Any help is appreciated.
 





that will work, a simple electrolytic capacitor commonly sold for under 50 cents is what is described in the diagram.

Welcome to LPF. Enjoy your time with us here.

mat.jpg


I have compiled a list of "must read" information, it will make your time with us more productive and pleasant.

Laser Resources (for n00bs and veterans alike!)

http://laserpointerforums.com/f36/looking-build-laser-read-me-47684.html

Sam's Laser FAQ (The Laser Bible)

http://www.repairfaq.org/sam/laserfaq.htm

RP Photonics Encyclopedia of Laser Physics and Technology

http://www.rp-photonics.com/encyclopedia.html

I have included a handy guide to assist you in finding what you need. ;)

search.gif
 
Thanx for the help guys.

I have heard that instead of a driver i could just solder a capacitor directly to the diode.

Does this work?
 
don't hesitate to ask for help along the way... we want you to succeed in your project.
 
photonaholic said:
don't hesitate to ask for help along the way... we want you to succeed in your project.
Click to expand...

I looked on the Radio Shack website and I can't find the variable resistor.

Do you know where I could get one, do I have to have one?

EDIT: Is this it?
Also is 18 gauge wire good to use?
 
Last edited:
You can use a fixed resistor in place of the pot. Decide what current that you want to run your diode at. For example, 420mA. The reference voltage of the LM317 is 1.25V. The resistor required is 1.25 / 0.42 = 2.976 ohms, you could use 3 x 1 ohm resistor in series.

The 18ga wire should be fine.

The pot in your edit is a behemoth! If you have room in your project for such a beast, go for it. Otherwise maybe use the fixed resistor.
 
billg519 said:
You can use a fixed resistor in place of the pot. Decide what current that you want to run your diode at. For example, 420mA. The reference voltage of the LM317 is 1.25V. The resistor required is 1.25 / 0.42 = 2.976 ohms, you could use 3 x 1 ohm resistor in series.

The 18ga wire should be fine.

The pot in your edit is a behemoth! If you have room in your project for such a beast, go for it. Otherwise maybe use the fixed resistor.
Click to expand...

O.K. so in addition to the two 10 ohm resistors i need a couple of other 1 ohm resistors depending on how many ma I want to run the diode at.

If i want to run the diode at 120mW how many 1 ohm resistors do I need?
 
According to the calculation I gave you, 1.25 / 0.12 = 10.416, so a 10 ohm resistor would do. We are talking total resistance here, the other two 10 ohm resistors in the schematic are not used as well. This calc gives you the total resistance needed.
 
billg519 said:
According to the calculation I gave you, 1.25 / 0.12 = 10.416, so a 10 ohm resistor would do. We are talking total resistance here, the other two 10 ohm resistors in the schematic are not used as well. This calc gives you the total resistance needed.
Click to expand...

Sweet! Thanks for all the great info. Just to be sure, a dvd burner diode runs at about 120mW right?
 
You must log in or register to reply here.


Back
Top