You need the resister for both AC or DC. that drops the voltage.

If you are using AC then you need s diod in line to turn in to DC.

hope that helps.

If operating from AC power, you can eliminate the diode if you use the LEDs in pairs.  Connect red of LED #1 to black of LED #2, then connect black of LED #1 to red of LED #2.  Now connect this to track power using one of the supplied resistors.

Stan2004, If iwanted to hook up all fifteen of these led's on one string,what would be the easiest way to do that?,what i have in mind is to either buy a string already made up to run on track power to light up underneath my second level,or make it up myself,it would be a good learning experience for me ,if i could do it i was going to try this once before,but i never got around to it.

Gerald Marafioti posted:

Stan2004, If iwanted to hook up all fifteen of these led's on one string,what would be the easiest way to do that?,what i have in mind is to either buy a string already made up to run on track power to light up underneath my second level,or make it up myself,it would be a good learning experience for me ,if i could do it i was going to try this once before,but i never got around to it.

What exactly are you trying to illuminate when you say "underneath my second level"?  For general illumination on a layout I think most guys would use one of those 12V DC LED strips, much cheaper and no resistor(s) and no soldering/wiring to mess with...

Note: It might not be obvious from the eBay listing but those LEDs are extremely small and relatively difficult to work with.  An 0402 LED is only 0.04" x 0.02".  If wiring up 15 of them for general "area" illumination rather than specific indicators like a headlight, tail-light, etc., I'd look into 12V DC LED strips/strings as shown below.  They are typically 3 LEDs per 2" segment (as shown); another option is 6 LEDs per 2" segment.  These are DC and we can discuss what it takes to make them track-power compatible if this is an option for you.

Stan,it isn't so much as to provide general illumination,but rather to just create a different mood around the trains,i don't know if i am explaining what i want correctly, but i just want to put a few lights in different areas,even using a different color,such as yellow,or orange led's of course,those two colors are actually the one's like the most, the led reels you mention are a possibility,& when i think about it Evans  Design has the led's allready made up to run on track power. I just wanted to try & make up my own so maybe i could learn something about how to put these things together,but maybe i am biting off more than i can chew,but it is still fun to try.

You can do that with LED strips. They can change color and brightness all from a handy little remote control. We use them above and below kitchen cabinets to do that very thing. Change mood and seasons.

Cheap too... amazon

I seem to remember seeing pre-wired, including resistors on the big auction site.  My 1 piece of advice is to try to plan ahead for your led needs because you could end up with a variety of LEDs using different voltages which gets to be a pain to keep track off.

Ed

Just to be clear, the resistors control the current to the LED, that is why you always have them, even if you think you are running them at the "right" voltage.

LEDs "run" on current, i.e. they have a nominal voltage they work on, but the current is the thing that controls whether it works or not, burns out or not.

Incandescent light bulbs are the opposite, they have a nominal current, or wattage, but it's voltage that controls whether they light or not and whether they burn out.

So you should calculate the dropping (current limiting) resistor for LEDs carefully. There are many "LED calculators" on the web, just google it, or you could go to my web site:  http://www.elmassian.com/index...onics&Itemid=453

Greg

While I don't disagree with the "careful" calculation of the LED currents, one thing to keep in mind.  It's allowable to use less current for the LED's without any issues, it's allowing the LED current to exceed it's rated current that kills them.  I routinely run LED's at less than their maximum rated current, and in many cases it's necessary to achieve the desired result.  Marker and class lights for locomotives is one such instance, I hate it when the class lights are brighter than the headlights!

Absolutely John, every LED spec sheet I have seen shows minimum, typical and maximum current. Also, today's LEDs (I used my first ones in the early 70's) do not require to run at max current to get good brightness, as it was when they were first on the market. Many people just use 20 milliamps when 10 will do.

(Sorry John, I guess I am kind of repeating what you said, but reinforcing not going to the max is important so it does bear repeating)

On the calculations of the current limiting resistor, the best ones are when they include the forward drop of the LED, especially when you run everything from lower voltages. The way to know this is the calculator will either ask for the forward drop of the LED or it will tell you it is making an assumption for you. But not to worry, if you don't, the "error" is on the side of lower current to the LED so you don't run any risk of damaging things.

Greg

p.s. not everyone does this, but an electrical engineer will tell you if you are running an LED from AC that you should put a regular diode in series with it. Not everyone does this, and it does not ALWAYS fail if you don't.

I will point out that I used LED's for headlights, markers, class lights, etc. with just a dropping resistor for several years, but I got several of them back with dead LED's.  Since I've used diode protection, no such issue.  If you have two LED's from one A/C power source, for instance markers, class lights, or dual headlights, you can simply connect them in opposite polarity in parallel and let the unlit LED be your "diode" to protect against reverse voltage.  If you're running them from the outputs of a TMCC system, you can't use that trick as in command mode you have half-wave rectified voltage for the lighting output, but in conventional mode you have full-wave A/C, so a diode is advised.

Most LED's have a max peak reverse voltage specification in the 5V range, so applying 18 volts through resistor will expose them to around 12.6 volts reverse voltage.  The resistor tends to somewhat protect them, but from my experience it greatly shortens their life.  I expect to put an LED in and never have to revisit it, adding the diode tends to increase the chances of that happening.

I can see that there is a lot to think about,at least for me anyhow,but it is very interesting i will take it slow & see how far i get, the led's & resisters don't cost a lot of money,so i can experiment & with any luck i may learn something without breaking the budget.

Gerald Marafioti posted:

Stan,it isn't so much as to provide general illumination,but rather to just create a different mood around the trains,i don't know if i am explaining what i want correctly, but i just want to put a few lights in different areas,even using a different color,such as yellow,or orange led's of course,those two colors are actually the one's like the most, the led reels you mention are a possibility,& when i think about it Evans  Design has the led's allready made up to run on track power. I just wanted to try & make up my own so maybe i could learn something about how to put these things together,but maybe i am biting off more than i can chew,but it is still fun to try.

WeberCanyon4014 posted:

You can do that with LED strips. They can change color and brightness all from a handy little remote control. We use them above and below kitchen cabinets to do that very thing. Change mood and seasons.

Cheap too... amazon

Given what you're trying to do, I like the LED strip suggestion.   Yes, you can buy strips of LEDs of different colors...so a strip of white LEDs, or a strip of orange LEDs, or a strip of yellow LEDs, etc..  Or you can buy so-called "RGB" strips.  Each LED on these strips has 3 LEDs built-in (Red Green Blue).  By controlling the relative current to the 3 LEDs you can generate a full range of colors including white.  It can be tedious wiring up 3 circuits to adjust the RGB strip color so you can buy RGB controllers.  In this short video I show a basic controller ($1-2 on eBay, free shipping) wired to a RGB strip.  

In this case I press the "color" button on the remarkably tiny controller and it cycles thru a range of colors.   Hookup couldn't be simpler.  You apply 12V DC and the controller directly connects to the LED strip as shown.  There are wireless remotes for not much more.  There are fancier controllers with wider color selection, programmable cycling through colors and intensity, and so on.  On eBay just search for "RGB LED strip" and you will get thousands of choices. 

eBay: 151699798468

 Party Festival 5M RGB SMD 5050 Strip light 300 LED With 24 Key IR Remote 3 Color, about $13 shipped.

Gunrunnerjohn, Now you got me thinking again about getting what your last post shows,very interesting we shall see. John, i just looked them up on e-bay & they are super bright, not what i am looking for,i prefer something not as bright,i am not trying to light up any particular area with a lot of light i just want a more relaxed feeling,but thanks for posting that.   Jerry  M.

I have some of those multi-color strings, they're fun around the Christmas holidays. (I'm still allowed to say Christmas, right?)

You can dim them from the controller, they can be bright, but they can also be very dim.

Those multi- color strings are ok for some situations,but i am drawn to just 2 colors right now yellow & orange for the purpose that i am looking for,& YES you can still say Christmas as many times as you like.

Well, the controller would allow you to set one two or any color you like.

Oh... Christmas...Christmas...Christmas...Christmas...Christmas...Christmas...Christmas...

Hey John ,You are giving my brain a good workout,i am not use to so much thinking at one time,as usual you make a good point, i will keep that information stored in my brain ,somewhere  i am running out of room to keep all of these ideas.

Plug a FLASH drive into one ear.

I might have to do that !!!!!!!!

GUNRUNNERJOHN, In your previous response showing the led  color reel,remote control,& a white item with 2 wires coming out of it ,what is this white thing for? ,i have e-mailed the seller twice trying to find out & they don't seem to understand what i want to know,also there is no power supply that comes with it,i would need 2 reels of led's to do what i want to happen,this item only comes with 1 reel,can i order another reel of color led's from another source without any problems,& how big of a power supply do i need ?  The e- bay # was151699798468. Thanks, Gerald

The whit box is the receiver, the remote talks it via IR like a TV remote.  The power supply is a 12V 2A DC power supply for one 5 meter roll, and you just add them up if you string more than one together  For three strings, you'd need a 12V 6A DC power supply .  In truth, they don't usually take 2 amps for a single string, but that's their specification.

There are tons of these on eBay, just search for 5M RGB SMD 5050 Strip light.

How about an even better price and a US seller, quick delivery?  It also comes with a better remote.

eBay: 111871923967

John, With these remotes can you just lock in on one color without it constantly changing colors,or flashing ?, i would just want to be able to stay on one color indefinitely.

Yep, you can pick any color steady, changing, flashing, or what.  You can also pick any intensity.

Thats good John, this last one you mentioned, i sent an e-mail to the seller asking about a second reel,or 1 ,10mm reel,& a power supply to match because i would need about 30' ,to go all the way around under my second level i am waiting to hear back from them ,i will keep you posted on how things go.

Remember, you can put the two IR controls together in one place in the center of the 30 foot run.  Face the little sensors out right together.  Then you will have control of both strings with a single remote.

Now thats something i would need a little more help with, i will wait & see if the seller responds to my question ,but i am glad you suggested that because of my lack of knowledge about these things every idea that is brought to my attention is a big help to me,this way i have a better chance of getting it right the first time.

Jerry ... I agree search "LED Strip lights " on Amazon ... you will see a whole new world of lighting, and great for train applications. The big roll John posted is a typical 16Ft. ~ long you can cut them for the length you want on the cut marks every 3 inches. RGB are the multi color ones the controller can do all sorts of things, also available are single colors. They have indoor / outdoor with a clear rubber..Silicone coating and indoor only without the coating just bare LEDs. You will also see short strips with a few LEDs . They are all 12vdc. You won't need to deal with resisters and diods, bridge rectifiers and such.

Good luck ,, Rick  : )

John ,I was thinking about what you said about putting the 2 IR controls together so i would have control of both reels with a single remote,could i just connect both reels together & use just 1 IR controler ?

You can't connect the two reels together with that particular string as they'd draw more current than the power supply/controller would deliver.  Other options on eBay would work, I have some that I bought that have 6A controllers, and you just buy a matching 12VDC power supply.

In my sun room I have 2 sets of 2 RGBs each with a controller, the controller sensors are right next to each other, like 1/4 inch apart, and it does not work for me, strips keeps getting out of sync. I am working on a fix to control both with 1 controller, with requires a 2 channel controller , which is another long story, ..... What you can do and it works is, if this fits your application, is connect 2 strips end to end, and insert a Hitlights LED Light strip amplifier booster , search on amazon,  between the 2 strips and power the first strip and the booster each with the standard little 2amp plug in power supply ( usually sold with the strips, but also sold separately ) More than 2 strips connected end to end exceeds the current limit for the first strip. I used the booster method to light up the wall on 32 feet of the layout in different colors, and it works fine.

Hope this helps ...Rick

Oh yea ... the booster is the one for $ 8.49

Interesting Rick, thanks for the input.  This may not be an issue for Gerald as he wants to set them to a setting and then leave them.  I know that the IR link isn't the most reliable unless you're pointing right at it, probably the issue you have.

There are plenty of higher capacity controllers, so there's no reason to have to use that solution in any case, it's just one method.

Rick, Thank you for the suggestion,but it seems more complicated for me , i need to keep things  as simple as possible, i tend to get very frustrated  very quickly,as John has said i need to find the right combination of parts to put this together,i know that for you guys with more knowledge this is a simple thing to do,but for me it takes me much longer  because of my lack of knowledge,but i am looking on e-bay ,hopefully i will find the things i need.

John ... my problem is not aiming the handheld, I wish it was, I have tried all angles and distances, I am going to install a controller with 1 Chanel output, 24 amp, the same signal will go to all 4 strips, in place of the 2 little 6 amp controllers.

While I have your attention........ Thank You for all your knowledgeable support on the Forum ... I  enjoy and have learned from your posts.

Rick

You're most welcome Rick, glad you find some use for my drivel.

I'm not sure what's going in in your case, I just dug two of the controllers and two RGB strips out of the closet.  I taped the little sensors that are on a short wire together and tested a single controller.  They tracked just fine, I never had it get out of sync.

John ...Thanks for taking the time to check ... I extended the 2 IR sensor wires about 3 feet to get to location the controller could see. I will duplicate what you did with 2 other new ones to see if that solves the problem.

Thanks for the info ... Rick

I'm at a loss why they'd get out of sync, it's a one-way interface and they're just IR receivers.

What are the pro's & con's of using  either the IR remote,or the radio frequency remote to work the multi color led reels ?,i have been looking on e-bay & i was wondering if there are any big differences,there seems to be mostly IR remotes being used, i don't see many offering RF remotes .