- Why do we need the 10k Ohm resistor as a pull-down resistor after the push button and what would happen if we left it out?
- Why is it necessary to define the digital pins 3-5 as inputs?
wouldn't it also be possible to just use the Arduino's 5V to supply the LEDs with current? (Maybe to be able to make them blink individually?)
The LEDs and the resistors are in series. Why don't we need to put the resistors before the LEDs and why apparently does the sequence in a series circuit not matter?
I'd like to find out what the smallest resistor value would be for this circuit. How can I calculate the resistors needed value with the formula R = U / I? (U must be between 1,6V and 2,2 V for a red LED, correct me if I am wrong, but what is the value for I?
I would also like to know the same for the pull-down resistor: what would be the lowest value for this resistor and how can I calculate it? R = U/I : U should be 5Vs but how can I find out I?