Talk:Controlling a solenoid (TIP120 Arduino)

newbies like me will ask the following questions: - why a 2.2k resistor in the connection between the tip and the arduino pin? - Looks like a diode between the connectors of the solenoid. what is it, why is it there? - also, while this is about solenoids, really this is a tip tutorial, not a solenoid tutorial, so maybe the name of teh article should reflect that...?