Mini LED's novice


santafewillie

santafewillie

Same Ol' Buzzard
Despite being into model railroading for 35 years now, I have never worked wit mini LED's before. I bought some Minitronics brand ones several years ago that I just haven't gotten around to installing. What I do know, is they're +/- sensitive, but beyond that I know next to nothing. I am assuming that the red leas is the - lead Here's a picture of one of them with the supplied resistor for using with 6V power source.
01-05-20 002.001.JPG

I have two questions.
1) Does it matter which direction the resistor is connected? Their very brief description (no instructions) indicates that it is a 33r resistor.
2) Can a single resistor be put in line with two LED's or should I use separate ones for each?
Thanks in advance.
 
I'm in pretty much the same boat, Willie. So, I''l be watching for any and all guidance. Hopefully, we'll have someone on here who will take the time to post a basic tutorial. I know this info can be found on the internet, but maybe we could get the basics explained and have it all in one easy to read place.
 
it doesn't matter which way the resistor goes in, and you should run seperate resistors for more than one LED
 
In DC wiring red is always positive and black is always negative. If you wire it the other way you are asking for trouble.

Resistors have no polarity and can go on either wire.

You don't have to run separate resistors for each LED unless you are powering so many that it will pull too much amperage through the resistor, in which case you have a different problem.

The important thing to know is what value resistor to use. That is indeed a 33 ohm resistor (you can read the color bands. There is also a rude little ditty to help you remember the order the colors go in that I won't repeat here.)

If you are going to run that on 6 volts then 33 ohms might be a little low, but it depends on the LED a bit. The LEDs I just put in my loco with DCC needed a 680 ohm resistor, but that's for 12 volts.

There are calculators out there to help you determine the resistor value, but you need to know some info about the LED which you probably don't have.
 
in your photo above, it looks like the darker one is blue, not black ... if it is blue, then that should go to the common positive .. which is blue on decoders ..
 
wvg_ca said:
in your photo above, it looks like the darker one is blue, not black ... if it is blue, then that should go to the common positive .. which is blue on decoders ..
Click to expand...
The dark one looks black to me (then I'm further away). I get ones wired red and black. The ones I'm trying now have very fine wires (hair like) and are twisted, which makes them easier to use, but stripping is a bit tricky. If my new camera will co-operate (I seem to have Terry's computer luck with cameras), I'll take some pics of the install I'm doing now. (remember to breath).
 
This is the guy I've been buying off and the 0805 SMD LED's I use to glue to 1.5mm Fiber Optic cable (suits Athearn H'light holes)
https://www.ebay.com/itm/12-x-pre-t...ghts-Pre-soldered-lamps-lighting/401598929206 and the 0603 for replacing the ditch light bulbs
https://www.ebay.com/itm/12-x-pre-t...ghts-Pre-soldered-lamps-lighting/401749234132
He usually has them also with the wires lying flat lengthwise, in line with the long dimension of the SMD. May be out of them at the moment. They are better in the ditch lights.
 
Don't forget to choose the warm whites from the drop down menu. I tried some of the cold whites but they had the bluish tinge to them.
 
i made a bunch of them maybe seven or eight years ago, for ditch lights, but i put the resistor on the back of the led itself, neater [ i used smd resistors]
 
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twforeman said:
In DC wiring red is always positive and black is always negative
Click to expand...
Oooops! I knew that, I just typed the wrong symbol.
Thanks for all of the information. That is the resistor that Minitronics supplied with the lights to use for 4v-9v power supply. They supplied a different one to use with 10v-16v. These will be used as floodlights on the side of a structure lighting the truck parking area.
wvg_ca said:
it doesn't matter which way the resistor goes in, and you should run seperate resistors for more than one LED
Click to expand...
Thank you also. The wire is indeed black, but that seems irrelevant. There are enough resistors for each light.
 
wvg_ca said:
i made a bunch of them maybe seven or eight years ago, for ditch lights, but i put the resistor on the back of the led itself, neater [ i used smd resistors]
Click to expand...
That must have been one of the very tiny resistors found on the circuit boards that some manufacturers are using when mounting to the frame behind the head lights etc. Most are doing it that way now. Haven't seen the insides of the newer Athearn Genesis locos that have LED's factory installed, yet. Would be about time. So nice to be able to remove the shells without a tangle of wires connecting to the chassis.
 
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