Question

How many voltage levels are present when a pin uses digitalWrite()?

(a) 1

(b) 2

(c) 3

(d) 4

I had been asked this question during a job interview.

Query is from Digital Input Output topic in division Arduino Programming of Arduino

Answer 1

Correct choice is (b) 2

To explain I would say: The digitalWrite() function can be used to send out two voltage levels; 0V and 5V which correspond to the digital LOW signal and the digital HIGH signal respectively. These voltage levels can however vary from board to board. For example, in some Arduino Boards the digital HIGH signal corresponds to 3.3V instead of 5V. Hence even if the voltage levels are different here, the meaning of the signal remains the same.