Hi all, I'm fairly new to electronics but learning as I go via Arduino and other resources. One question I had upon completion of project 2 was the purpose of the 220-Ohm resistors connecting to ground. As far as my understanding goes, resistors are primarily used to reduce the amps going into the loads (the LEDs in this case) that way they don't get overloaded or burn out as quickly. Also, I was under the assumption that the load uses all the amps during this process, and that (theoretically) the voltage between the source and the ground should be zero according to Kurchoff's Law. I was thinking the digital pins have something to do with this but I'm not sure.
Addtionally, I'm curious as to the purpose of the 10-kO resistor also connecting to ground in regards to the switch. I have yet to go into further projects yet, so I'm not sure if this is covered later on, but any information would be much appreciated.