I'm not very knowledgable with LED's, so forgive what might be a dumb question.
I see that MRC sells these Light Genie LED's in two different sizes with what appears to be a resistor already installed, unless I'm mistaken: https://www.modeltrainstuff.com/Lighting-s/2048.htm?searching=Y&sort=3&cat=2048&show=30&page=1&brand=MRC
My question is, can I connect these LED's directly to the light outputs of a decoder without a separate resistor? And if not, does anyone make LED's that size with a resistor already integrated?
I'll be converting a small HOe narrow gauge diesel to DCC which doesn't currently have any lights, and it doesn't have very much extra space at all.
You really need to know what decoder You will be using and what the light outputs are capable of before choosing LED's. Some decoders have resistors on the board. The link to the SMD's do not have resistors built in, aside from that SMD's are usually used for buildings or with light bars in engines. You're best to go with a cone shape LED for headlights, usually a 3mm or 1.8mm. Here is a link to different size LED's of all sorts that come already wired with resistors and or bridge rectifiers if needed. You need to pick a decoder and go from there.
http://www.modeltrainsoftware.com/miniatureleds.html
Take Care!
Frank
Another option I use, on the link that Frank posted, look on the left, click on Hobby LEDs, than scroll down, and find Chip Nano Pico, or Mega LEDs, They have a "plug-n-play" set with the rectifier/resistor already installed. They are good for 7 - 19 volts.
Mike.
My You Tube
Mike,
One of the drawbacks of using the already set-up rectifier/resistor chips is the fact that the circuit takes up some room, so when space is at a premium, like in an engine with decoder it's hard to find space. I have been using a few of the Nano's when space will allow, but have also been using the Pico's set-up for 6v 12v use where the resistor will fit inside a 3/32 brass tube. I use them for the scratch built brass yard lights and street lights. Brass lamp shades with port hole lenses from Athearn F7's for the yard lights and clear acrylic tube for lenses in the street lights.
I was thinking of using something like a TCS M1 or something similar in size.
So one of those chip LED's would be fine to connect to a light output of the decoder, I'm assuming with the 7-19v option?
Well Frank, the leads after the resistor are long, but you can shorten them to your needs, and the leads between the LED and resistor are some what long, depending on what your using them for.
I use them for ditch lights, some headlights. The "ready to install" is what attracted me. I have noticed that they are bright, using them with DCC power, as my ditch lights are much brighter than the head lights, unless I use them for headlights too. On this loco, I used them as ditch lights. I could probably add another resistor to dim them some, I think.
I believe You would be better off going with the 1.8mm 3volt LED's with built in resistor. But it is hard to say without seeing what You want to put them in. The chips come wired with magnet wire and not all that easy to work with for a novice lacking experience, but that's My Opinion.
https://www.tcsdcc.com/Customer_Content/Literature/Decoders/HO_Scale/M-Series/M1BEMFWEB.pdf
You must have been typing same time I was..... don't get Me wrong...there is nothing wrong with using the Nano's or the Pico's especially ditch lights, which by the way are too new for My era. It's just that not everyone can shorten magnet wire and solder them back again for the length they need.
I have a couple Athearn Genesis SD75M's that have ditch lights, but 1.7 bulbs that look pretty good...but I think I run them twice in 15yrs. Going to the Grandkids.
Your photo looks great!......does look like You could tone them down a bit. If We could see what the OP wants to put them it....would help.
Here's some pictures that should help: https://drive.google.com/open?id=0B1g3jaAXRYTldEFxaWNLM2VVWGs
The first picture is a side view of the chassis and shell.
Second picture is a top view. The pickups are connected to the motor with diodes?, so I'll have to remove them, right?
The third and fourth pictures are the front and rear view. Between the chassis and the shell there's only 2/32" in the front and 3/32" of clearance in the back. Which is why I need such tiny LED's to fit in that space. The front already has a clear headlight lense but I'll have to drill a hole for the rear light.
Here's the parts diagram too, if it makes any difference: https://www.roco.cc/doc/ET/1/DE/31025_8579.pdf
Wow! these "critters" are right up Dave's (hon30critter) alley! Maybe he'll chime in and get you in the right direction.
Mike
Wow, it looks like even the smaller SMD LEDs are too big to fit within the light castings on that one. The Light Genie once absolutely will be, because the LED is mounted on a little circuit board with a resistor.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
According to the website posted above the chip sized LED's should fit.
I intend to mount them flat behind the lenses, for example on the gearbox in the front and on the motor for the back.
Is it really that difficult to splice and solder that magnet wire? The lengths of wire those LED's come with are way too long so I'd have to shorten them.
Also, does anyone know how many volts the light outputs are on a TCS M1? If they're low enough I wouldn't need the large resistor that comes with the 7-19v LED's; I could use the 12v ones instead.
WM#734,
Well that critter is a horse of a different color.......but no sweat....the Pico chips will work, I guarantee it. Get the ones in the 6-12DC set-up, they come with resistor connected already.....DO Not get the ones in 7-19 volt set-up that comes with the rectifier and it difinitely will not fit. Go back to My pic' of the lights laying down the all brass ones, the second light laying down with a tiny thing sticking out the lamp shade is a Pico chip.....it's smaller than the head of a pin. You could use clear epoxy cement or Jewlers cement to glue them right to the lense. I drill a little hole in the lense and use Jewlers cement which drys crystal clear to glue them.
The link is for the Pico's...but they are for the ones with the 8'' leads...You can get smaller leads at the time You order them.....any size You want and they will make them for You with appropriate resistor, just ask, there is no special price for that.
http://www.modeltrainsoftware.com/smd-chip-leds.html
I just picked up a critter for My friend in the UK that i will be sending Him soon by Athearn which is a EMD Model 40...it looks to be close in size to Yours.....It comes with front/rear LED's, but they mount theirs on the PC board that sits in the cab on top of the motor.
I'll keep following this thread to see how it goes....I have a lot to do today!
Thank you for the advice. Just to make sure, connecting the 12v LED's to the decoder won't be any problem? The track voltage will be around 16-17v. This will be my first hardwired decoder install, so I appreciate all the help.
One more thing, do I have to worry about polarity when connecting the LED's?
12V LEDs will be fine - technically there is no such thing, a 12V LED is an LED with a resistor already connected. It may be too bright though, you may have to add a laerger value resistor - or just get ones without resistors and connect your own. The SMD LEDs are quite bright when run even ad a medium current level (half way between 0 and the maximum it can take). For the full-size LEDs I use in most headlights, a 1K resistor is good, but for those SMD LEDs you may need to use 2.2K or even 4.7K.
Magnet wire is just different. You can't bend it too much, or it will break off. The insulation is clear enamel. If working with a long thenth you can just wrap the end in a piece of sandpaper and wipe it off, but for short pieces it can be removed with thinner or acetone, or in some cases just burned off with the soldering iron.You don't want it rubbing against anything metal - it will wear the enamel off and then cause a short.
wm #734 Thank you for the advice. Just to make sure, connecting the 12v LED's to the decoder won't be any problem? The track voltage will be around 16-17v. This will be my first hardwired decoder install, so I appreciate all the help. One more thing, do I have to worry about polarity when connecting the LED's?
No You won't have a problem with the Pico's. Yes You do have to have the polarity correct. The magnet wires are Red for + and Green for -. If You are going to use the decoder You mentioned it does have the capability to control the Led Brightness.....look at the link I posted for it.
I have cut and installed longer wires on the magnet wire or even shortened the wire and found there was no need to strip the enamel from the wire when soldering....but I use Silver Bearing solder paste, which makes soldering them so musch easier. I use 1/16 heat shrink tubing on the joint, which also will take up some room, so I recommend, do your measuring accurately for the length You need and then maybe a little more. They state that the Pico's will last 2yrs if they are lit continously, or they will replace them free.
BTW: I use this type cement for gluing to the lenses....it is not ACC/CA. Also using for all window glazing in any Model.
http://www.artbeads.com/gs-hypo.html?utm_source=gs-hypo&utm_medium=shopping%2Bengine&utm_campaign=googleproducts&gclid=Cj0KEQiA3Y7GBRD29f-7kYuO1-ABEiQAodAvwAeD3MSh-7Wk3_KJWXgjVFyCeq5iK_fZLpt4FkTCpEcaAqTL8P8HAQ
Good Luck!
Thank you everyone for all the help. When I get around to doing it I'll take pictures of each step and post on here.