Resistor for red in TCSS crystal

[scott]

Hi - looking for guidance in the optimal size and spec resistor for the red in the TCSS crystals. I calculated the proper resistance and it suggests 1.8ohm/1.8W, and TCSS says the closest they sell is 2ohm/5w. I have over resistored the red because the specified closest is the fat white block that doesn’t fit in any of my builds. I have done this 10+ times and they work and last, just finally got annoyed with how dim the red crystal is in the Kylo I just built.

Thanks!

[darth_chasm]

3.7v battery I’m assuming? Given the results you posted you’re calculating your resistance at 1 amp! The crystals have 5mm leds in them. They are only supposed to be run at 20mA. You need something more like 80-100 ohm 1/8 watt.

[scott]

Yep...brain cramp over here, thanks!