Hello, I am working on a project in which I use an Arduino Mega to control a robot. I am more experienced as a programmer than an electrical engineer and my team is still a little inexperienced with electrical circuits. Here are a couple questions that I have:
When using a PWM pin, does the current or the voltage decrease as the duty decreases?
Each digital pin fires at 40mA on an Arduino board, considering that the upper limit on draw is 500 mA for the entire board, I have can't fire very may pins before the limit is reached. The Arduino itself is only switching transistors in this project, which have very low current requirements on the base to perform the switch. Is it possible for me to reduce the mA given off by a pin by adding a resistor to the circuit, thereby increasing the number of pins I can use?
Can I use any single ground-pin as a common ground for all of my output pins (both PWM and digital)?
Is there a difference between any of the ground-pins on the board?
How much current does the serial port consume when it is sending and receiving information (it is connected to the USB port which corresponds to pins 0 and 1)? I assume it is at or less than 40 mA, but I would like to know because I am working with a lot of pins.
These are just some basic questions that I have, thank you in advance