Thanks for the help, I will be ordering some. From the responses, I think I will make a large order and fit them in several locations. I will keep y'all informed of what I do with them. I think several structures and many locomotives will benefit from them.
Perhaps it would be a good idea for CTT to do a article on these and give an objective look at the benefits of led verses incadecent and vise versa.
dennis
TCA#09-63805
Dennis, Richmond controls has "golden white" LEDs: http://www.richmondcontrols.com/
As for circuits, simply wiring a resistor in series is okay if the voltage never reverses polarity. The problem is that otherwise the reverse voltage can easily be greater than the LED can stand. For directional lighting with DC motors, a simple solution is to use a single ballast resistor for both forward and backward LEDs. Wire the LEDs in parallel with each other, cathode to anode, then put the resistor in series with that. That way, each LED protects the other.
Often, modern DC locomotives have diodes in series with the motors, apparently to keep them from starting at low voltages. If you can identify these, you can put the lighting circuit across the motor-diode string instead of just the motor. This gives less variation in brightness with voltage, which is already much better with LEDs than with incandescents.
The resistance to use depends on the supply voltage and the LED's forward voltage, which can be as high as 3.5 volts for blue and white LEDs. The voltage across the resistor is the difference between the supply voltage and the LED's voltage. Divide that by the rated forward current, and you have the resistance. Be sure to calculate the power dissipation also. It is the square of the current, multiplied by the resistance. Or the square of the voltage across the resistor divided by the resistance. Or the voltage across the resistor multiplied by the current through it. You may find that you need a higher power rating than you thought you did. It is a good idea to overkill the power rating, by a factor of 2 or more, to keep the resistor cool.
I would not simply wire a bunch of LEDs in series without a ballast resistor. They are very sensitive to voltage variation and will go off with just a slightly low voltage and be burned out by just a little too much voltage. The purpose of the ballast resistor is to get around this sensitivity.
Bob Nelson
For the use in Locomotives Leds can be used in place of the headlight/ taillight etc, but not the way postwar bulbs where placed. Leds focus their beam forward, so when you put them upright behind the lens in a postwar GP9 the way the original bulb was placed, you'll only get a small glimmer instead of a beam. You will have to find a Led with the right diameter to fit into the hole where the lens is and replace the lens with the Led.
Best is, directional headlights on even a dirt cheap K-line S-2 switcher is easy by simply wiring the Leds parallel to the motors. The motors run on DC, so when they change direction, the + and - change position. Since the Led is a rectifier, it will not emit light if polarity is switched. Thus making a directional headlight.
Use a resistor in front of it, about 680 Ohms i guess will be sufficient or wire multiple Leds in series. The average voltage for a Led is between 1.8 and 2.5 volts, so to make them working without frying them at 18 volts wire 7 to 8 Leds in series or use the resistors.
I have Leds in my parts box as small as 1mm and as big as 10mm, all kinds of different shapes (triangle/ square/ rectangle) which are ideal for billboards and structure lightning. They use very little power, you can even feed them by using conductive paint or wire used to make electromagnets (very thin wire, not bigger then a human hair). That makes the powerlines almost invisible. I've even seen policemen (on a h0 layout) having flashlights which actually worked. The figure had leads for the power made by conductive paint across the figure and then after that dried, they where repainted in original colors. You couldn't tell how they got power to those flashlights!!
1688torpedo wrote:CSXJohn- Those lights would look great on a Jif Peanut Butter Billboard or even a Cream of Wheat version! Take Care.
Keith : let's hope they don't use them for a Gritts sign !!
Dennis : I got mine at Hobbytown in Mentor Oh. They are a regular Walthers item in HO, so you should be able to get them from them or a hobby shop that sells Walthers stuff. Not sure what is available in your area, but I sure could send you some if you can't find any !! Oh, these are part # 933-1094 , HO Wall Mounted Lamp.
Thanks, John
Bob and John, thanks for the replies and for the information. I think I will order some and start doing some retro fits. Where did you order these lights from? That is for both Bob and John. I think they will go great on the new layout.
Dennis
A great topic again Dennis !! I don't know about the engines or rolling stock, but I stumbled on to these little, actually HO lights that are perfect, I think, for our O gauge structures !! I think Frank 53 pointed this out a while back, so I can't take credit for it, but check them out, maybe ! Here is a picture of the package of 3 they come in.
Here is my application of one that I installed already on an Atlas switch tower ! I just drilled pit the hole where a dummy plastic one was supposed to go !!
I plan to put them on station platforms & factories or anything !! How about a billboard ? !!
I have several projects in the works including benchwork. On those days that I am not working on benchwork, I thought I would do some engine repair/tune ups. I would be interested to hear from those who have replaced incadecent lights in the engines with L.E.D.s. I know that these are directional in that you can get forward focused, side focused, etc. What did you do and how do you like it? Would you keep it or not?
Also, if you have done this on scenery, ie house lights, station platforms, etc.
Thanks in advance,
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