Hello Arduino community.
I've been looking at some commercial boards and I see some kind of capacitors on them that I don't quite recognize.
My guess is they are polyester capacitors?
Here's an example (red circles):
I have a few confusions about this board:
1- What type of capacitors are these?
2- When should I use them and why are they being used here? There are ceramic caps on the board as well, so the manufacturer has deliberately decided to use this type of capacitor for certain parts instead.
3- I'm assuming that capacitor in the middle next to the big IC is a decoupling capacitor. I've always heard that you use 100nF ceramic caps for decoupling but this board is using this type of capacitor. Why?