Additional LED resistor

Hardware, PWM, and Optics
1

Hi, I added a 5mm white LED to the X1 port of my 40mm v1.5 pioreactor. I just connected it to the B port of the HAT via Dupont cables. Do I need to add a current limiting resistor or is it built into the HAT PCB? I set the intensity to 100% and the LED flashed briefly then died. I then connected a new LED and set the intensity to 30% and it has been running fine for a few hours. Do I need to be careful with the intensity setting or just add a resistor?

Thanks
Al

2

Hi @AGreen, the LED channels on the HAT output up to 100mA. The HAT controls the current (via a constant-current driver), so you don’t need to add a resistor. You should check the white LED’s datasheet for it’s maximum current allowed though.

3

Thanks @CamDavidsonPilon understood.