Total novice that can solder

[quickrick]

  Well I mocked up my project today as follows; 10 mini leds in a row along with 1/2 watt 550 ohms resistance.  I applied my 41 volts of DC voltage and got nothing.  Even when I removed all but 120 ohms I still got no light.
I have many ideas but no solid proof that I even know what I am talking about concerning these bulbs.
                                                                                                       A) Could it be that I have the polarity wrong on each of the leds? B) Could it be that they don't like the series wiring?  C) Can it be that they can operate on 120 volts?  D) Does it matter that I'm now running them on DC voltage?  E) If I mailed one of you guys a sample set of bulbs could you "ID it or are you absolutely sure I have 3volt leds here?  F) Last, Is it possible for an led to run off of 120volts AC?  I'm flumoxed on this one, ideas? Thanks QR

[justDIY]

i think a good place to start would be with a single led.

grab a 3v button cell or a pair of AA batteries, and test a single led ... find out which way is what, and then work up to something like a 9v and three leds

can you toss up a picture of these led lights?  i can't believe they'd have internal resistors, but anything is possible.

[quickrick]

Okay, I did hook up 2 AA (3Volts) batteries to determine polarity. They did light albeit not too bright.  I then went to an old 9 volt making 8.14 volts with no resistor, it was way too bright and before that 560 ohms inline with the 8.14 old battery(9 volt) and it looked just about right measuring about 5.5 volts.    http://flickr.com/photos/60259282@N00/319256520/            http://flickr.com/photos/60259282@N00/319256518/in/photostream/                                                                                        QR       

[quickrick]

Guys, thanks for all the support on my little science project. I settled on the 560 ohms of resistor and the 36 volt source (really 40 volts ) and ended up with the correct brightness for 50 hours or more burning. I'm sure that this fused set up is safe to use in our house after the garage floor testing now. I will try and show you a picture of the illuminated chili peppers (the reason for all of this) when I'm finished. QuickRick

[justDIY]

awesome ... looking forward to the pictures!

[quickrick]

DIY, check out the pictures of my hot/hot Chili Peppers! Was it worth the effort?, yes in the fun factor. They should last a long time! Thanks for your help, QuickRick





edit by Rob: fixed image URLs

[justDIY]

great work!

one thing I might recommend, if you feel like it, replace those white leds with red ones. a 'white' led is really a blue led with some yellow phosphor on it.  when they are on, you get blue + yellow = white.   however, a red led is pure red, essentially you'll get much better coloration of your hot peppers this way.  of course, it'll change all the specs we worked out :/

[quickrick]

justDIY, yes you may have something there and now I realize that even an amatuer can do this stuff. I sort of want to burn out some of these bulbs for now and space considerations were paramount: the pepper opening is tiny.
I'm really pleased, and I learned  lots. Thanks, QuickRick           p.s. 2 things I'd want next time; brighter and redder. Would those run off of my 40volt pack? (10 peppers)

[justDIY]

using 2 red leds per pepper (think tiny 3mm leds), they'd consume nearly the entire 40v, so you'll only need a small resistor ... and boy 'o boy would it be bright red.