user39624: I am fairly new to Arduino. When I am experimenting with circuits, do i need to worry about shorting out a pin if I accidentally connect the +5V pin on Arduino to an input pin on Arduino without a resistor? I just want to make sure I avoid destroying the board when learning how to create circuits. 

user39624: No, no short. Arduino (Atmega) pins default to inputs. Pins configured this way are said to be in a high-impedance state. Input pins make extremely small demands on the circuit that they are sampling, equivalent to a series resistor of 100 megohm in front of the pin.
Answer provided by Look Alterno and converted from a comment.

39624: <p>I am fairly new to Arduino. When I am experimenting with circuits, do i need to worry about shorting out a pin if I accidentally connect the +5V pin on Arduino to an input pin on Arduino without a resistor? I just want to make sure I avoid destroying the board when learning how to create circuits. </p>
 39624: <p>No, no short. Arduino (Atmega) pins default to inputs. Pins configured this way are said to be in a high-impedance state. Input pins make extremely small demands on the circuit that they are sampling, equivalent to a series resistor of 100 megohm in front of the pin.</p>

<p><em>Answer provided by Look Alterno and converted from a comment.</em></p>
