I have been interested in this particular switch with a built-in LED.
According to the website, the forward voltage for the LED inside the switch is "about 3 V". It then goes on to recommend a resistor of ateast 220 Ω resistor as do some other sources. I plan on powering the LED through the Pi Pico VBUS pin which, if I understand correctly, is roughly 5 V. Also, after some research I came to the conclusion that the blue LED is most likely in the 25 mA current draw ballpark. So with that info in mind…
5 V – 3 V = 2 V
2 V / 0.025 A = 80 Ω
Now, although the current draw was a guess on my part, I figured that even if it is slightly different than the number I gave it wouldn't be enough to change what I am trying to convey. I don't quite understand the disparity between what articles say and what Ohm's law seems to say.
Ohm's law, at least on paper, seems to indicate a resistor in the ballpark quite a bit lower than the 220 Ω I see on Adafruit as well as other articles. Is it just because 220 Ω is much more standard and easier to find? If so, will the decreased current resulting from the 220 Ω resistor cause enough of a difference in brightness in the LED for it to matter, or can I just use 220 Ω and be done with it?