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LED info

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  • Member since
    March 2001
  • From: US
  • 111 posts
LED info
Posted by turbine682 on Wednesday, March 16, 2005 8:20 AM
Good Day!

I am always trying to learn more, so here is a cool site that gives a little info about working with LED's. (I have little electrical knowledge, except for block wiring by Atlas)

www.theledlight.com

I also downloaded some LED calcalator form lsdiordes.com, but am still learning basics and terms.

Any other infor you have about working with and understanding LED's is greatly appreciated.

I'm not that concerned about redoing headlights, but would really like to do lighting for buildings, street lamps, etc.

TIA,

--Ed
Pennsy's Q2's rock and so do C & O's H6's & 8's but the best is NYC's J3a's
  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Wednesday, March 16, 2005 9:04 AM
The key thing to remember with LEDs is that they operate on CURRENT not voltage. Thus, you ALWAYS need a resistor to limit current to a safe level. LEDs also do not like current applied in the wrong direction - an ordinary diode can stand up to this, but LEDs really can't. So your power source should be clean DC power. Don't use an old cheapy train set power pack, for example.
If you downloaded the calculator, then you have a method of figuring out what resistor to use. When figuring the LED current, there's really no way you can determine what value to use other than the manufacturer's specifications for that particular LED.
When it comes to building lighting, the generic white LED does a good job of representing fluorescent lighting. They tend to have a slightly blue tint to them. They're also good for modern diesel headlights. For older nits I prefer the 'golden white' LEDs which have a more yellowish color to them when lit and look more like an incandescent light bulb.

--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
    January 2004
  • From: Crosby, Texas
  • 3,660 posts
Posted by cwclark on Wednesday, March 16, 2005 9:16 AM
I use a lot of LED's on my layout and layouts from the past...they make great searchlight targets, panel lighting, and for locomotives; using white light leds facing fiber optic strands to the headlights make a wonderful, powerful locomotive headlight...Chuck

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,255 posts
Posted by gmpullman on Wednesday, March 16, 2005 12:55 PM
Bi-color LEDs are just the ticket for simple panel indications when using Tortoise switch machines. I just wire a pair cathode to anode and put the remaining leads in series with one of the legs of the motor supply. One LED will be green, the other red then insert them into your panel for the appropriate track designation! E-Z
No resistors needed as the switch motor acts as the current limiter!
On my layout all "normal" switch routes are green so I can tell at a glance if any switch is set for "Reverse"
Ed
  • Member since
    January 2013
  • 180 posts
Posted by 2021 on Thursday, March 17, 2005 4:16 PM
LED's and any electrical device operate on current and voltage. The current limiting resistor drops the voltage thus reducing the voltage to the LED. Less voltage to the led means less current and power over a fixed resistance.
Ron K.
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Friday, March 18, 2005 8:32 AM
I have a friend who did a lot of reasch into LEDs for his RC airplanes. He explains the basics of LEDs and the current limit resistor. He also has a calculator at the bottom of the page to detemine the size of resistor needed. I have his permission to post the address here:

http://www.rc-cam.com/led_info.htm
  • Member since
    January 2004
  • From: Chiloquin, OR
  • 284 posts
Posted by Bob Hayes on Wednesday, March 23, 2005 6:09 PM
Check out www.ledmuseum.org
It has just about everything you need to know about leds.

Bob Hayes

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