Ok guys I used Rwenzing's cardomain page last time to find out how to install LED's in my 4wd switch etc but now I can't find it. I had a 5mm blue LED with the 470ohm 1/4 watt resistor and the LED like the page said but after about a month the LED burnt to a crisp and smelled my cab up! I don't understand why. Anyhow I bought some green 5mm LED's from the shack that are 2.1v they say on the front but I dunno if this resistor is gonna let it burn up again or not? Can someone help! Thanks

 

This might be of some help on the resistor values:
LINK

I entered 12v with a 2.1v drop, a 20mA current and got a resistor value of 560ohms.

You could use a slightly higher value resistor than the 470ohm, although it will make the LED slightly dimmer... you probably won't notice the difference.

About the only thing that will fry a LED is too much current, so it's possible the 470ohm wasn't really a 470ohm (a 10% +/- range is normal).

I'd try a 560ohm resistor to start with, next maybe step up to a 1/2 watt resistor if the 1/4 watt tends to get hot.

 

https://www.ranger-forums.com/f59/ho...rt-leds-62796/

 

Well I was using a 470ohm like it said to use and it was on a 3.6v 20ma I believe 2600mcd LED and it burnt it up. I tried using a 1k ohm resistor and it did the same thing! So I dunno what to do. I have a 2.1v 630mcd green LED in there now with a 470ohm and it is doing just fine. I am stumped. I just want a working light bulb in my 4wd switch!!!

Brandon, thanks for the link but that isn't actually what I am talking about. Thanks though!

 

Does that 2600mcd LED put out enough light?

The LED's I use are 8000mcd for blue up to 15,000mcd for white.

The calculator shows a 560ohm resistor @ 14.4v for a 3.6v LED & 470ohm @ 12.5v for a 3.6v LED. If your getting somewhere closer to 14.4v when running, it could be that the resistor just wasn't resisting enough

For the 2.1v LED, it shows a 560ohm resistor @ 12.5v and 680ohm @ 14.4v.

If you have any resistors in the 500 - 700ohm range, you could always swap them out to see if it helps.

I've got a bunch of LED's & resistors, if you want to try some just let me know.

 

Yeah it is pretty deng bright @ 2600mcd. And I used a 1k ohm resistor on the last one I put in there and when I turned it on it smoked and i immediately turned it off and it smelled HORRIBLE lol. I was like wtf? I used 1k ohm this time. And last time I used a 470 ohm and it worked fine for a month or two before it burnt so I dunno what I am doin wrong :(

 

Hmmmmmmm

The only other thing I can think to try is swap the resistor from the + to the - side of the LED (or vice/versa), it shouldn't make any difference, but it's worth a shot.

 

Well I have always had the resistor on the - side and it is working just fine right now for my little un bright green LED that is in there now lol

 

You could always forget about the resistor and get a fixed voltage regulator.. i have some 1.5v and 5v ones iv used on a few projects, you can get them all over ebay of at shadyorack for 10 times the price.

 

Fixed voltage regulator?? What is that?

 

LOL - regulating off 10+ volts is a big fail.

 

If that remotely came close to making any kind of valid sense, it would almost deserve a response. Since it does not, i will be passing off any opinions related to your uninformative response along with its capitalized brief acronym to denote great amusement...

moving on... sorry it took so long to get back to the thread jwad, i haven't checked it or my email in a few days, and jp7 do your research before you try and "educate" others.

A voltage regulator is just a simple IC that takes a voltage between certain ranges in, and puts out a fixed constant voltage, for example the LM1086 series of voltage regulators come in a few different fixed outputs along with an adjustable one, the 1.8 - 3.45v fixed can hand up to a 27v input, the 5v fixed can handle up to 25v input, and can support up to a 1.5amp load.

They have given me loads of different options in a lot of my projects in the past, it may actually be a little more difficult then just the resistors in line with the led, but it all depends on your application, one would eliminate the need for an in line resistor but youll still need to run wiring for power/ground and the fixed output to led lead, and youll still have to solder the connections.

I read the rest of the post, check the data sheet that came with the leds you have, not all leds have the same reverse voltage capabilities, that may be the reason why its burning up.

 

I've done too many LED projects, and have too many writeups on this site to take the time and re-explain all of the things I do. You can search if you want to learn.

 

edge2k isn't a noob, he's done some serious work himself, you both have a great amount of skill and knowledge

 

Seriously though...

You could use a T0220 2v or 3v voltage regulator with a resistor to power an LED. I've never tried anything under 5v, but I'm sure it could be done.

It could be that the LED's are just bad & won't hold up.

 

Chyea but my j-beeb style haircut makes me cooler.

haha, by no means am i trying to start a pointless argument or question the skills of another, but the comment only would only contradict and further more make it difficult to find a solution, iv put my .02 cents in, jall can take it how you want from there.