LEDs with built-in resistors

Hi all....

Is there anyway of visually distinguishing these from normal LEDs?

I am totally certain that I'll mix them all up....

Paint them black before you put them away.

KenF:
Paint them black before you put them away.

That might be a wee bit drastic, but I was thinking a small dot of Tipp-Ex or similar.

Strip a bit of bell wire and chop the removed insulation into very small lengths. Push one of these onto one leg of each LED.

KenF:
Strip a bit of bell wire and chop the removed insulation into very small lengths. Push one of these onto one leg of each LED.

Yeah but then I will have to remember if the insulated ones are the ones with the resistor, or without 8)

Good idea, actually....

To save having to fiddle around with tiny rings, First you push the tube slightly over the leg, then snip, then push it the rest of the way on.

JimboZA:
Yeah but then I will have to remember if the insulated ones are the ones with the resistor, or without 8)

Use the orange insulator for the ones with resistors built in. When you forget, PM me and I'll tell you what colour it was :slight_smile:

When you get them you will notice a black spot you can see through the plastic on the side. All the ones I have ever had are like this.

Alternately you keep them together in a zip locked plastic bag with a label on them, just like surface mount capacitors. They look all the same but have different values.

Great Mike, thanks: I was hoping there would be something evident. Keeping them quarantined is waaaaay too simple a solution :wink:

Hmmm well I don't see anything like a black spot. But I hooked them up to 5V without using an external resistor and they draw 12mA so the built-in one is clearly in there, somewhere.

They're 10x the price of normal ones, but well worth it in terms of less faffing around.... long as I can tell them apart.

Where's the Tipp-Ex?

I have looked for these and found red, green and yellow.

Did you find any other colors or RGB ? Where from?

Thanks,

Nope they had only red 5mm, which is a pity but no biggy.

I got them at a supplier called Mantech here in Johannesburg.

I've never come across these before but I suspect I may have had some. I had a few LEDs that wouldn't give any output unless I gave them 5v with NO series resistor. (part of a mixed bag I picked up). Since their behaviour confused me I, eventually, threw them out. Had I known that such devices exist, they may have been useful.

Something characteristic seems to be that the ones illustrated have coloured encapsulation.

Coloured encapsulation seems to have largely "gone out" with the advent of full-performance (I hate the term "high-brightness" - earlier LEDs were simply poor efficiency, current ones are just efficient) components, it was intended to enhance visibility but then only if in a relatively shaded location. With decent brightness, clear encapsulation enhances the efficiency and readability further (as long as the surface is not in a position as to be reflective of ambient light). And of course, multi-colour and white LEDs necessarily have clear encapsulation, though possibly frosted.

So in general, I can mostly assume that coloured LEDs in my collection are obsolete.

Having so many clear ones can be tricky, so a LED tester is very useful.

Hi, if you have a DMM with diode test, test a resistor LED and a non resistor LED, they should have different forward bias characterisitics.
And NOTE the difference on a label on the inside of the LED container.

Tom.... :slight_smile: