I am using an Arduino to control an electric lock strike but I don't know how to power the lock with sufficient power. To control the lock from the Arduino, I am using a TIP31 transistor (It is NPN). The transistor will be getting the signal from pin 9 on the arduino and will connect to the ground wire of the lock strike. Since I will only need the DC barrel jack for positive (since the ground wire of the strike will be connected to pin 9 via transistor), I need to know whether this barrel jack will draw power from a power source even though it will not be connected to ground.
P.S. The lock strike needs 12VDC.