Hi, I'm working through the Arduino Starter Kit lessons, and on my current lab (#4- Color Mixing Lamp), I'm trying to understand the logic behind the selection of a particular resistor.
Basically, you have a phototransistor (data sheet is here) connected to a 5V source. On the emitter side of the phototransistor, in series, is a line to the Analog In and then a 10 KOhm resistor, then finally a line to ground.
Can you explain the rationale for selecting this 10KOhm resistor? Can you frame it in terms of Ohm's law? Also, please explain the relevant details from the datasheet and how you were able to infer all this (bc I don't follow it at all).
Thanks so much!