Go Back   Aquarium Advice - Aquarium Forum Community > General Aquarium Forums > DIY Projects
Click Here to Login

Join Aquarium Advice Today
Reply
 
Thread Tools Search this Thread Display Modes
Please support our sponsors and let them know you heard about them on AquariumAdvice.com
 
Old 02-25-2007, 12:11 PM   #11
Aquarium Advice Addict
 
SparKy697's Avatar
 
Join Date: Nov 2006
Location: Northwest Indiana
Posts: 1,495
Quote:
Using resistors will I be able to hook up more then 3 leds on a 12v adapter?
Yes. If you hook the LEDs up in parallel and use a resistor to limit current. You can use as many LEDs as your power supply can handle.

LEDs by nature will drop roughly 3.6 v across their leads. With a 12 v power supply that leaves 8.4 volts that you have to figure out what to do with. This is where the resistor comes in. By adding the resistor in series with the LED, you can give the unwanted voltage a place to go and be used as heat. It also gives you a way to limit the amount of current the LED gets passed through it. In this drawing you see a 500 ohm resistor in series with the LED. Since we know the voltage across the resistor and the value of the resistor itself we can use ohm's law to calculate the current through it. 8.4v/500 ohm=.0168A (16.8mA) This is well below the max rating of the LED of 30 mA.

In our circuit below you can see that the power supply is rated at 1000mA this means the we can use 1000mA/16.8mA=59 LEDs wired up the same way and the power supply will handle it.

And yes, the amount of current passing through the LED is what controls it's brightness. You can even exceed the rated max if you like by using a smaller resistor, the device will just not last as long.

Keep in mind that these values only exist in the perfect world. Each resistor will not likely be 500 ohm and even the LEDs will not all drop 3.6v either. Some experimenting is always required.
Attached Images
File Type: jpg led_circuit_683.jpg (52.8 KB, 63 views)
__________________

__________________
-Joe
"...but the guy at the LFS said I needed it!"
SparKy697 is offline   Reply With Quote
Old 02-26-2007, 06:36 PM   #12
Aquarium Advice Regular
 
Join Date: Feb 2007
Location: indiana
Posts: 88
Send a message via Yahoo to donk1667
sweeeeeeet looks great joe
__________________

__________________
75 gal,planted,co2,diy defuser,gw ferts,l,223 watts of usable light 3 wpg,rena xp3 & marinebiowheel 350 "taking out biowheel" and lots of help thanks all!!!and the plants come from a MAD SCIENTIST ;]and now the fish15harliqun rasboras,7neons,8cardnails tetras,6 black skirt tetras,3flying foxes,3 algae shrimp,6zebra dannios,1rubber lip,1redtail shark[i]
donk1667 is offline   Reply With Quote
Old 03-02-2007, 11:43 PM   #13
Aquarium Advice FINatic
 
Join Date: Jan 2007
Location: NJ
Posts: 662
Nice job. This is now my next project.
__________________
C/
chase33 is offline   Reply With Quote
Old 03-03-2007, 12:34 AM   #14
Aquarium Advice Addict
 
plecoperson's Avatar
 
Join Date: Apr 2006
Location: Evanston, Illinois
Posts: 1,245
Quote:
Since we know the voltage across the resistor and the value of the resistor itself we can use ohm's law to calculate the current through it. 8.4v/500 ohm=.0168A (16.8mA) This is well below the max rating of the LED of 30 mA.
Oh, right. Ohm's law. Of course.

What the h**l are you talking about, Sparky? What's a resistor? LED? I barely know what the letters stand for. I hate you and redswi because you're evil and know how to do things that should be beyond the scope of human ability.

It needed to be said.

Oh, right-the lights are cool. Whatever.
__________________
-Lisa

Remember that Darwin was mostly right!
plecoperson is offline   Reply With Quote
Old 03-03-2007, 01:11 AM   #15
Aquarium Advice Freak
 
Join Date: Dec 2006
Posts: 265
Thanks for the refresher....I havn't thought about ohms law in a long time...I need to make a support rail for a glass cover on the corian tank, and after this post I think I'll add some leds to the rail...


BTW are you as hurt as I am???
Quote:
I hate you and redswi because you're evil and know how to do things that should be beyond the scope of human ability
__________________
40gal community - wet/dry/sump -1.8wpg - planted w/Brazilian Sword,Melon Sword,Anacharis,Bannana plant,Crypt,Hornwort,Java moss
Fish - 3 Neons-1 Chocolate Albino Pleco-1 Gold Spot Pleco-2 Lavender Gouramis

55 gal QT/Breeder/Experiment
http://www.aquariumadvice.com/viewtopic.php?t=91209
http://www.aquariumadvice.com/viewtopic.php?t=95417
redswi is offline   Reply With Quote
Old 03-03-2007, 01:26 AM   #16
Aquarium Advice Addict
 
SparKy697's Avatar
 
Join Date: Nov 2006
Location: Northwest Indiana
Posts: 1,495
I'm not sure I will ever get over it.

Some things just don't heal
__________________
-Joe
"...but the guy at the LFS said I needed it!"
SparKy697 is offline   Reply With Quote
Old 03-03-2007, 09:41 AM   #17
Aquarium Advice Addict
 
plecoperson's Avatar
 
Join Date: Apr 2006
Location: Evanston, Illinois
Posts: 1,245
Quote:
BTW are you as hurt as I am???
Quote:
I'm not sure I will ever get over it. Some things just don't heal




to you both. Devils.

-Lisa
__________________
plecoperson is offline   Reply With Quote
Old 03-03-2007, 09:46 AM   #18
Aquarium Advice Addict
 
SparKy697's Avatar
 
Join Date: Nov 2006
Location: Northwest Indiana
Posts: 1,495
Ok, I feel better now
__________________
-Joe
"...but the guy at the LFS said I needed it!"
SparKy697 is offline   Reply With Quote
Old 03-20-2007, 11:38 PM   #19
Aquarium Advice FINatic
 
Alshain's Avatar
 
Join Date: Apr 2006
Location: Tyler, TX
Posts: 823
I'm curious, why 100 degree viewing angle? Is that because you wanted it to hit the reflector? The reason I ask is because I want to add additional moonlighting to my Current USA Sattelite fixture and I was going to do it replacing the existing two with 18000 mcd superbright bulbs and 100 Ohm resistors, but they only come in 30 degrees, I thought that would be enough to aim down at the tank.
Alshain is offline   Reply With Quote
Old 03-20-2007, 11:53 PM   #20
Aquarium Advice Addict
 
SparKy697's Avatar
 
Join Date: Nov 2006
Location: Northwest Indiana
Posts: 1,495
Quote:
I'm curious, why 100 degree viewing angle?
I chose the 100 degree LEDs because I did not want to see beams of light in the tank. I found that by placing these about 5 inches apart in an 18 inch tank gave me good coverage overlap and you can not tell where the light originates from. You can certainly use the 30's, I believe you will see more of a column of light in the water. If you like that look you are in business.

HTH
__________________

__________________
-Joe
"...but the guy at the LFS said I needed it!"
SparKy697 is offline   Reply With Quote
Reply

Tags
diy, light, lights

Please support our sponsors and let them know you heard about them on AquariumAdvice.com

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
DIY MoonLights Liquid_Pyro DIY Projects 12 05-15-2009 12:25 PM
DIY Moonlights Dewey DIY Projects 2 07-02-2005 03:08 PM
Finished my DIY LED Moonlights mentallylost DIY Projects 6 05-17-2005 07:28 AM
HELP! DIY moonlights not working! Tripoli DIY Projects 77 06-22-2004 12:01 AM
DIY Moonlights Joshsmit56001 DIY Projects 4 12-03-2003 06:09 PM







» Photo Contest Winners








Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -4. The time now is 06:30 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.