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More LED help

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  • Member since
    July 2006
  • From: North Dakota
  • 9,592 posts
Posted by BroadwayLion on Tuesday, January 16, 2018 12:16 PM

Were your LEDs wired in series? :ION tried that, all have been removed and replaced with Parallel wiring.

 

ROAR

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Here there be cats.                                LIONS with CAMERAS

  • Member since
    October 2006
  • From: Western, MA
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Posted by richg1998 on Saturday, January 13, 2018 12:29 PM

I have used 1k, 1/4 watt resistors for some years. Allows about 9ma current with plenty of brightness.

Below is a link you might like.

http://www.members.optusnet.com.au/nswmn1/Lights_in_DCC.htm

You can also Google led's series parallel and get lots of link.

I know a few here don't like using google but it has never failed me in many years.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by BATMAN on Saturday, January 13, 2018 12:23 PM

Try this array wizard. It is for dummies like me.

http://led.linear1.org/led.wiz 

 

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

  • Member since
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  • From: Reading, PA
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Posted by rrinker on Saturday, January 13, 2018 12:20 PM

 I suspect the simplest cause - the club power supply was significantly more than 12 volts.

What value resistors did you use? If the LEDs are rated for 20-25ma, you want to design to something well under that - half would be a good point, so about a 1K resistor. They will be plenty bright for building lights. And that leaves plent of head room so that even if connected to a power supply putting out 24 volts, they wouldn't blow. 

 Also, did you use 1 resistor per LED, or try wiring some in parallel with a single resistor?  Parallel LEDs can lead to a cascade effect since the current changes when one blow out - the rest will all be over current and you get a chain reaction. 

 Series resistors are OK, if they are all the same. For 12V you can get away with 3 in series, you need to calculate the resistor based on the LED voltage, adding up all 3. 

 Best is just 1 resistor per LED, then you know it's right. And since bulk resistors are less than a penny each, it's not expensive.

                                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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  • From: New Brighton, MN
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More LED help
Posted by ARTHILL on Saturday, January 13, 2018 12:09 PM

I wired a large building with LEDs It worked fine on my bench with my 12V power supply. I took it to the club and wired it to their 12 power supply and it blew some but not all the bulbs. Theye were not the flash burn out that I get when I forget the resister. It took a while.  I don't even know what questions to aks. Anyone up to consulting with me here?

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