LED's

This section talks about both LEDs in general and more specifically White LED we use for lights.  Here are some quick background links if you have a specific question.

If you do not know what a LED is, go here:  http://en.wikipedia.org/wiki/Light-emitting_diode

If you want to know how to calculate the LED resistance value, go here: Resistors for LEDs/Bulbs

If your not sure what the voltage polarity of a given LED is, go here: LED Polarity

This section covers:

1) COMMON LEADED LEDs SHAPES AND SIZES
2) WHITE LEDs
3) SMD LEDS (No leads)
4) WHERE TO GET LED's
5) WHERE TO GET MAGNET WIRE


COMMON LEADED LEDs SHAPES AND SIZES

Large LEDs come in many physical form factors with Round and Rectangular being the most common.   Lens come in clear or colored.  See the picture on the left.

The LEDs most commonly seen and used as headlights are the round "T" series of LEDs with the T1 being the size of choice.   Today these same series of LEDs go by other names reflecting there physical size.  

T1-3/4= 5mm diameter &  T1 = 3mm diameter.

In the picture on the left, the 5mm is the larger round LED with the 3mm being  the smaller round LED.  Also shown is a rectangular LED.

When one is replacing a given light bulb used for a headlight, the clear white 3mm is the common LED size to use.

The next picture shows 2mm LEDs.  They have a unique shape with a wide base and a long round lens tube that is 2mm in diameter.  This  tube can be used to replace any plastic light pipe portion of a round headlight such as dual beam headlight of a HO Diesel engine.







The 1.8mm diameter LEDs are similar to 2mm LEDs but the lens is very short and rounded.  Furthermore, there are variations of this package where the leads come out the sides.  







WHITE LEDs
The best white LEDs for trains are not standard common white LED's.  They are vary from pure white or white with to much blue tint.   For trains we want LEDs with yellow tint to them.   Sunny White, Yellow White and Golden White are color names for White LEDs that look like incandescent light bulbs.  Sunny White are for modern locomotives.  Golden White are for Steam Locomotives.

There are other colors like "Yeloglo" that are similar but the color distinction is NOT so well defined as above.

What if you only have standard White LEDs?  There are alternatives such as making your own "Sunny White" like LED using stains on a standard flat white LED clear lens.  One such stain is the "Tamiya Acrylic X-26 Clear Orange paint".


SMD LEDS (No leads)
Surface Mount Device (SMD) LEDs offer a much more compact light source than the common round "T" series LED's but they have NO WIRE LEADS.   SMD LED's come in various sizes such as shown on the left.  The most common LED for our use is the "0603" size (2nd from the left).  The number "0603" refers to its physical size as in 0.06" by 0.03" (inches not mm).  Smaller versions are available (0402 is shown on the far left followed by smaller 0201's) which are sometimes called "Nano" LEDs!   

The challenge is connecting wire magnet wire leads to these super small SMD LED's.   Here are some YouTube videos on how to do this. 

0603 Leds:

Nano LEDs:


TRAINTEK's Special LED TOOL is shown on the left.  One clamp holds the LED while the other clamp holds the fine 38AWG wire you solder to the terminals of the LED.  The TrainTek store listed below specializes in the tools and magnet wire you need to attach wires to these LEDs.  

See "Where to get Magnet Wire" below for more information.



WHERE TO GET LED's

Some suppliers will sell SMD LEDs with leads on them for a price.   This is a classic time/skill versus money tradeoff.  Here is a list of LED distributers/dealers that are not in any order.

1) Unique-LEDS
A generic LED place has all colors of LED's including SMD versions.  This LED site is only one of many others like this.  The colors may or may not be realistic for railroad headlights but at least this place has some pictures of the colors.  You will have to explore the website to find what you want.

2) Litchfield Station
Complete assortment of LED and lighting options.  They are a dealer of Richmond Controls LED's below.

3) Richmond Controls
The Best Source for Sunny White and Golden White LEDs for trains PERIOD!  The offer SMD LEDs with wire leads.  My supplier of white LED's.  However it is best not to buy directly from them.  Use a hobby shop such as Litchfield Station above.

4) LED-SWITCH.
A small company located in central North Carolina specializing in LED's, Toggle Switches and other model railroad electronic supplies.  Like other generic LED sources, there is no clear definition of the various "white color" LEDs.  You will have to explore the website to find what you want.

5) TrainTek
A Hobby Store that primarily focuses on digital train control products and services.  They stock lots of parts including SMD LEDs (nano LEDs) and the small 38 AWG wire you need to make you own leads for them.  They even have a special tool for holding the SMD LEDs.


5) WHERE TO GET MAGNET WIRE

Magnet wire is copper wire with a clear color insulation on it.  

Historically magnet wire was covered with real enamel insulation.  If the wire was large enough, a combination of mechanism were used to strip off the insulation.  Typical methods were burning it off with a match or some flame source, scraping it off with a knife and using fine sandpaper.  However, as the wire gets smaller and smaller, the knife solution can cause the wire to become nicked and cause breakage when flexed.   Next heat can cause the wire to get burned.  Super fine sand paper becomes the only real option when dealing with fine magnet wire.

Modern Magnet wire is covered with a insulation whose melting point is the same as solder which facilitates easy stripping.  

To learn more about Magnet wire go here:http://en.wikipedia.org/wiki/Magnet_wire

1) TrainTek
A Hobby Store that primarily focuses on digital train control products and services.  They stock lots of parts including SMD LEDs (nano LEDs) and the small 38 AWG wire you need to make you own leads for them.  They even have a special tool for holding the SMD LEDs.