two LEDs wiring/power question

**Hermitjensen** · 06-19-2015, 06:22 AM

So i figured i had too many questions in my previous post and figured i should just put this last question on its own to stop it from being confusing. (sorry if theres a rule against posting this question in two places i just figured this question was getting lost in my previous post and thats why i havent gotten an answer in two days for something that seems simple, at least to me.)

For this saber staff im attempting as a first build which is just lights, no sound, i am planning to get the coupler that has slots to see through, and I have a (strangely shaped) quartz crystal and a 5mm blue LED.
Now if i did my math right which most likely i didnt..(hence why im asking for help lol)
If i used a 6v, 4 AA (or AAA) battery setup for one half of the saber only, could i run that blue 5mm LED with a 100ohm resistor and the amber cree with a 3.9 ohm resistor in parallel? or did i use the LED calculator (and my knowledge of electronics) incorrectly?
I just want to give my saber something besides the blades to light up and this was the first to come to mind.

Heres a circuit diagram in case my explanation wasnt clear.
circuit.jpg

**Silver Serpent** · 06-19-2015, 06:35 AM

Wiring diagram is correct. Resistor for the amber Cree is correct. I can't verify the resistor on your 5mm blue LED, since you didn't list the forward voltage on it. You could use the DynaOhm resistor for the accent LED, and it'll automagically give the LED 20mA. The DynaOhm has polarity, so be sure you put it on the + wire for the LED and pay attention to the markings on it.

Since you're using alkalines, I would definitely use AA if you can fit them in the saber. You'll get a much longer runtime over AAA's.

**Hermitjensen** · 06-19-2015, 06:53 AM

I got a bunch of the blue LEDs years ago and am not 100% sure on the details of them, but hooking up a multimeter to my little "test circuit" of the led and resistor with 6v, the multimeter reads 3v across the LED (assuming forward voltage is the same as voltage drop)