View Full Version : Accent leds on Crystal focus.

07-07-2013, 03:49 PM
Hi guys

Just a small question.

I'm waiting for my order of MHS parts but I'm already "working" on a second saber or an upgrade.
I just have a little problem. The owner's manual of the crystal focus 6.5 says : "The board outputs 3.3V / 18mA max per accent"

The thing is that I have a stock of led (a good friend gave me a box that contained 100 led of different sizes and colors for free, thanks again ;) ) but all the leds run at 20mA.

see where the problem is? The pads can only give 18mA but my leds need 20mA. Should I find leds that requires less mA?

Forgetful Jedi Knight
07-07-2013, 04:24 PM
No, you'll be fine. Just make sure you properly resistor the yellows and reds. ;)

07-07-2013, 04:58 PM
Ok thanks FJK

I'm gonna use the green leds i have. I use 2.2v 20mA leds. So if i'm correct : (3,3 - 2,2) / 18 = 61.111..... ohm
Will that work with a 68ohm resistor?. (if i bridge the resistor footprints). Or should i use 61.9 ohm 0603 SMT resistors?

Forgetful Jedi Knight
07-07-2013, 05:02 PM
2.2V for a green? Hmmm. A 68 Ohm 1/8W resistor would be fine.

07-07-2013, 05:25 PM
Ok thanks. No need to buy new resistors then ^^

07-14-2013, 09:00 AM
these links will help you in the future:



usually, colors like blue/green..etc are around 3-3.3v vF.. and other colors like yellows/reds are about 1.8-2.2v vF..

so 68 Ohms seems to be correct.. (if it truly is a 2.2v vF green led..)..

however... (not that it m maters in this case) but most leds, especially HB, SMD leds, can be lit up decently at only a few mA..