LEDs and resistors...help

[severdhed]

hey guys, i have a project I am working on where and i need some help.  i picked up a few LED tea lights at a dollar store, they are basically a flickering led with a silicone flame.  the LED is wired directly to a 3.5v button type battery without a resistor (there is a switch to shut it off).  i would like to take a few of these LEDS (2 to start with) and power them from the 5v line on a pc power supply.  i just don't know enough about these thigns to know what i need.  if they are running off of a 3.5v battery without a resistor, would 5v burn them out?  if so, how do i select the right resistor?  i have some assorted resistors in a box in the basement, they have different colored stripes, but i dont know what they mean. 

assuming i am using two LEDs, should i wire them up in a series or parallel?  does it matter?

help...

[RandyT]

I think you need to figure out what is making them flicker.  If there's a circuit built into the LED, then it may work fine at a higher voltage, or it may fry it.  I'm not sure simple LED rules are going to apply here. 

They only cost a buck.  Try one

[severdhed]

yeah, i was suprised when i opened it up and didn't see any kind of circuit board, i just figured they were some kind of flickering LEDs.  i'm tempted to just continue to run them off of batteries.  i dont want to give too much away, basically it is for an arcade based decoration.  im just not sure if i should leave it sitting on top of my cabinet and power it from the PC, or hang it on the wall and use the batteries to power it. 

i'm going to go play for a few minutes, perhaps i'll post some pics if i make any progress

[drventure]

I've used the heck out of those LEDs in my Cabinet. Picked up about 20 tea lights from big lots at one point.

I wired em up with 80ohm resistors direct to my LEDWiz. No problems at all. I found some specs online at one point, they're basically 20ma 5v leds, with a flicker circuit built into the LED itself. No resistor though, because the button battery won't generate enough current to blow it (but the LEDWiz will!)

Just recently, I used them while refurbing an antique floor lamp, I lit all the marble parts with those flicker leds and used a small AC-DC LED driver module for the power. Works great!

[severdhed]

i picked up a 2pack for $1 at the dollar tree, i wasnt sure how many i would need.  so since randyt pointed out that i wouldn't be out too much to try them, i wired 1 up directly to the 5v line on my pc power supply, it works fine, and still flickers.(there is clearly no separate circuit).  so i then proceeded to pull the led and silicone flame cover and mounted both LEDs inside one tea light unit.  i spliced the wires together and ran hooked them up to the pc again, they both light up and flicker quite nicely. 


you can see what i did with these in my project announcement thread...