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Main => Main Forum => Topic started by: rackoon on February 13, 2006, 02:59:08 pm

Title: Need Power source idea for 100 LEDs
Post by: rackoon on February 13, 2006, 02:59:08 pm

OK here's the deal, I am building a three sided cocktail cab and want to use close to 100 UV ( I'm going for that black light effect) LEDs. I have 26 clear buttons, 40 shinning down around the base and the rest will be shinning down under the control panels.

    I am planning to break them up into four circuits in case something goes bad later.

    The resisters that came with my UV LED's say that they work for 12v but they were free and I am willing to drop in (V) and get new resisters if necessary.

   I will have 110 wired into the cab and thought about taping into the computer power supply yet don't want to mess up the computer.

    So what I need is a cheap 12v AC to DC inverter that will put out enough amps to handle four LED boards with about 25 LED's on each.

    I was going to use a power supply that was similar to the ones that folks use to power things such as portable CD players. Yet when I went to  Radio Shack, the sales man said I was crazy then made me feel stupid by asking a bunch questions i couldn't answer specifically. Looking back, I should have walked over to the rack with the LED's hanging on it, grab the most powerfull one and say "I want to power 100 of these" on four separate boards.

I have done some searches and cant find the answers I am looking for. Can some one point me in the right direction?

Title: Re: Need Power source idea for 100 LEDs
Post by: whammoed on February 13, 2006, 03:08:29 pm

They are probably 30 milliamp which means you need 3 amps.  You can probably use a power supply that has 3 amps to spare on either the 5 or 12v rail. 
Or you can get a 13.8volt power supply like this:
http://www.radioshack.com/product/index.jsp?productId=2103960&cp=&kw=13.8v&parentPage=search
and get resistors for 13.8volts

(you can find supplies cheaper on ebay likely)

Title: Re: Need Power source idea for 100 LEDs
Post by: Buddabing on February 13, 2006, 03:21:54 pm

Get yourself an inexpensive PC power supply. You could use one of those AT-style boxes that you have in your closet. Take the number of rated amps on the +5 or +12 volts, whichever you will be using, and divide that by the number of amps needed to drive each LED (this will be a small number, something like .025), and that is the number of LEDs that the power supply can drive. A PC power supply will be able to handle that many LEDs with ease.

Newer power supplies can handle more load on the +12 volt line.