3 mm Warm White Through Hole LED's

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wombat457

Active Member
Staff member
#1
Do you think I can find these any where - nope I can't. Looked at Digikey (got confused and stopped looking after 13 pages) Allelectronics didn't even seem to list them under that name so I now have no idea where to go to get them other than evilbay and THAT is out of the question.

Any suggestions or does anyone know where on either digikey or allelctronics they hide these things?
 

fcwilt

Active Member
#2
Hi,

One of my "goto" suppliers has just one 3mm T1 Warm White part number in their online catalog - the downside is the minimum order is 50,000 - in multiples of 50,000.

The problem is the need for warm white - lots of white and cool white parts - just the one warm white.

Good luck.

Frederick
 

wombat457

Active Member
Staff member
#4
Well, I kept looking and found some here, albeit they are ultra-bright, they are also warm/soft. Also got some 2.4k ohm resistors.
 

fcwilt

Active Member
#5
Hi,

Just for grins I went back to check on the cost of 50,000 and this time the search did not bring up the same part number. Another part number that you could buy in multiples of one - but no stock until March.

Nothing I could do would find that original part - although my browser history would bring it up - odd.

In any case for 50,000 they are just 5 cents each.

Frederick
 
#9
Any suggestions or does anyone know where on either digikey or allelctronics they hide these things?
How about going to any store and look in the Chrismas lights section. I buy strings of 50 and manually extract the LED. Got piles of them that way. I, of course, usually wait until after Christmas when they are all 50% off. That way I think they ended up being 7 or 8 cents each. I also buy sets of red and green to use in control panels and the 1.5mm ones for signals.
 

wombat457

Active Member
Staff member
#10
Christmas lights will really work ... that would be a savings. Our local (decent) Dollar General sells 100 light lengths for around $2 and the Dollar Tree sells the lights for, yep you guessed it, a dollar.

So when you remove the LED's what then? Which side of the LED is which for soldering wires to them and for the resistor?

If I can get this to work, it will definitely be the way to go and will have a limitless supply!
 
#11
LEDs come in 3 basic wiring styles: radial lead, axial lead, and surface mount. Through-holes use only axial and radial. Radial means both leads come off the same side (actually the bottom). Axial means each lead comes off a separate side. Usually, the long lead is the positive, the short lead negative. If the LED has a flat on one side, that's the negative lead. If you can see into the LED, the large part is the negative, the small part the positive. If you're connecting single LEDs to the power source, it doesn't matter which lead you attach the resistor to.

wiring.jpg Here's what I mean by a single LED to the power supply.

series.jpg Here are 2 LEDs is series.

parallel.jpg Here are 2 LEDs in parallel. (not the clearest diagram, but it is accurate)

axial.jpg
Axial lead

radial.jpg
Radial lead

And for all who know what anode and cathode are, I'm trying to keep this in simple non-technical terms where ever possible.

Here's where things get technical. LEDs are constant voltage devices. The means if you supply too much voltage (even a little too much) the current used by the LED increases significantly and POOF - no more LED. However, it also means if the voltage is too low (even by a little bit), the LED will fail to operate. No damage, just no output. Each LED has a design current for maximum output (of light). These two factors, design voltage and design current, along with the supply voltage are used to determine the the value of the resistor. If the power supply voltage matches the LED's design voltage, NO RESISTOR is needed.

The whole point of the this is that a 2400 ohm resistor sounds awfully large. A typical LED connected to a 12 volt power supply would require a 500 ohm resistor.
 

Mark R.

Custom Painter
#12
I've gotten lots of warm white LEDs out of those Christmas light strings for dirt cheap. One set - after I snapped off the fluted plastic cover - has some really great 3mm LEDs with concave ends ! Initially I was rather disappointed they weren't round topped like a typical LED, but when illuminated they made a perfect representation of the old lights in early switchers and RS units. Perfect for steam engines as well. The filament shows the spot right in the middle and the concave lenses works just like a large reflector. Fifty of them for $2.99 ! Helluva deal.

Mark.
 

wombat457

Active Member
Staff member
#13
That is a great deal indeed. My wife has christmas lights around a couple of trains that are on shelves for display purposes. I took a look at them and the ONLY thing that makes me think twice about them is the length of them and how they would fit into an N Scale structure. Granted, they wouldn't have to be pushed all the way through whatever was holding them in the building.
 
#14
Christmas lights will really work
Yes, been using them for headlights for at least 10 years, probably longer. When I started using the Christmas lights a single LED from the store was something like $6, and light strings came out to something like $0.80 each.

So when you remove the LED's what then? Which side of the LED is which for soldering wires to them and for the resistor?
I don't have them in front of me but I believe I had to straighten both leads to get them to slide out of their "socket". When I did that I found the anode (+) lead was still the longer lead. In other words the Christmas light people didn't trim them to be the same length. This is a good thing for us. Another way to tell is that many (most?) LEDs will have a flattened part or notch on the actual casting. The flat or notch would indicate the negative (-) lead.

It does not matter which side the resistor is put on.
 

wombat457

Active Member
Staff member
#15
Thanks Horseman, I have a string of 200 white christmas LED lights that are just sitting around gathering dust, they wont be doing that much for longer.

One other thing, I assume they connected for an "in series" setup like any LED.
 
#18
Holiday lights sound like an excellent idea! I will be checking my local Wal-Mart.

For those who prefer not to dismantle strings of Christmas lights, 3mm Warm White Through Hole LEDs are readily available from several sellers, including:

Amazon
Streamlined Backshop
Model Train Stuff
Model Train Software
Lighthouse LEDs
Newark (Element 14)

Some of these sellers offer warm white LEDs in sizes other than 3mm, including teensy SMD LEDs for use in locomotives.

And don't forget that ginormous auction site -- dozens of sellers there offer warm white LEDs in any size you may desire.

- Jeff
 

wombat457

Active Member
Staff member
#19
Jeff,

Thanks mate,

I actually bought a 100 of the Lighthouse LED's and associated resistors. Pretty impressed with their service too so far.
 



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