Resistor Calculations check

**Renaissance Jedi** · 10-13-2015, 08:29 PM

I used the resistor calculator on the LED Center website to calculate my resistors (duh), and I ended up with some strange answers. I'm going to be using a PC v3.5 with either a 7.4v Li-ion 1050mAh 14650 Battery Pack or a 7.4v Li-ion 1400mAh 18500 Battery Pack, to power a RGRB tri-cree. The green die will be hooked up to the main LED pads on the board, while the Red and Royal Blue dies will be wired to the FoC/ colour mixing pads. The calculator told me that for the Red die, I should use a 15 ohm resistor that is 1.8 watt capable resistor, and for the Royal Blue die, a 12 ohm 1.5 watt capable resistor. Are these numbers right? I ask because TCSS doesn't offer these resistors, and I feel like it would offer all the resistors one would need to build a saber with this sort of set up. Did I do something wrong? Are there resistors sold by TCSS that would work?

**Silver Serpent** · 10-14-2015, 07:10 AM

Those numbers don't look correct at all. What values did you plug into the calculator?

Source voltage should be 7.4v. Forward voltages are listed on the Tri-Cree page in the store. Typical current is 1000mA.

**Renaissance Jedi** · 10-14-2015, 09:21 AM

Ah, I see my mistake, I entered 130 Minimum Luminous Flux @ 350mA for the forward current for green, 80.6 Minimum Luminous Flux @ 350mA for red, and 625mW Minimum Radiant Flux @ 350mA for royal blue. I simply entered the wrong value.
After entering 1000mA, it appears that I should use the 4.7 ohm 5 watt resistor for the royal blue diode, and then the 5.6 ohm 10 watt resistor for the red. Does this seem to be correct?