Soldering Problem

[Smiley]

First, a pop-quiz.

Please tell me what is wrong with this picture:



Anything missing? Anything out of order?

[Infoamtek]

For one, I'd say the limiting resistor.

[Smiley]

I see.....

Anything else?

[Infoamtek]

It's hard to tell from the picture, but the leads may be reversed. Did anyone check to see if it worked before soldering it together? Also did anyone check to see if the diode was rated for 9 volts?

[Smiley]

When it comes to this kind of material, I'll admit I'm poorly educated. What you see is a "trail run" of miniature lighting I plan on installing into a prop. When I was working on it, the diode did blip some light at first. But that is as far as I have gotten. I know it's not the battery nor bad wires (I've tried several of them). Perhaps I purchased a bad diode? I don't have instructions for this kind of thing, but pictures of something very similar; so I follow those.

What I want to create is a set of about 5 to 8 LED lights (10mm) running off of a battery source.

[scareshack]

heres a few links that may help ya some.
http://wolfstone.halloweenhost.com/H...#SimpleLEDEyes

http://led.linear1.org/category/led-basics/

[Smiley]

Ah, thank you.

[naberhoodhaunts]

nightstalker

It seems to me that most leds are 3 volt you need a reducer in between. i'm not a pro at this but that would be my guess.

[Gore Galore]

John is right,
the limiting resistor is missing.
And you need to make sure the red lead is attached to the pin that is connected to the flag in the led (HOT).
You can also use one battery to run 2 leds off of with no problem.

[mindtumor]

If it blipped and then quit working you probably blew the LED. LED's hooked up in that manner are basically just a short a across your power source.

[imax]

Yeah, the 'blip' is a dead- (ha ha, sorry for the pun) giveaway. You *murdered* a LED. Go get a resistor, and a new LED and try again. Killer.

-- I

[Smiley]

Yeah, the 'blip' is a dead- (ha ha, sorry for the pun) giveaway. You *murdered* a LED. Killer.

Hopefully it didn't have any family.

And you need to make sure the red lead is attached to the pin that is connected to the flag in the led (HOT).

Pin? Flag? Whosajigawha?

[Scottzilla]

I think the "flag" Gore Galore is referring to how when you look inside the LED one lead goes to a larger piece of metal (the one with the die and the reflector cup) than the other one. GG said hook the red wire to the "flag" pin but I've run into more negative "flag" pins than positive. The truth is there isn't really a standard for which pin gets the die so I usually just find the polarity by hooking it up and trying it.

Of course, always make sure to use your current-limiting resistor.

...unless that is part of your haunt. Killing LEDs in front of a live audience might be too graphic for some people. You should post a warning outside in your queue line.

[Smiley]

Okay, okay. What if.....

I hook up eight 5mm LEDs (20mA each/forward current of 17.6 total) to a 18volt battery source and use a 22 ohm 1/8W resistor? How's that?

[Infoamtek]

In series of parallel? This is an important question.