In the example circuit below (Arduino Uno R3), what would the equation be to identify the amperage going into pin 2 when the button is pressed? What if I used the 3.3v on the arduino or a 9v battery instead?
What is happening to the input pin when the button is not being pressed? (I assume it's a guaranteed LOW state due to any current being sapped by the GND, yes?)
What would happen without the pull down resistor? A short when the button is pressed? What would happen without the ground being connected at all? Anything?
A tutorial for how to choose a pull down resistor I seen suggested a resistance value of 10 times the impedance of the pin. I'm not quite sure where to find this impedance value, but I have seen on an arduino tutorial "A 10K resistor is a good value for a pullup or pulldown resistor." Just not much of an explanation of why that value.
Sorry for so many little questions in this one question, but these are the kinds of things I'm not seeing addressed in most tutorials.