Using ohm's law, V=IR, or V/I = R, we can determine the resistor value:
(5V-0.7V)/20mA = 215 ohm
so if I understand this right that means that with a 330 ohm less current is allowed to pass through but the voltage remains the same?
If your transistor has a gain (Hfe) of 50, then 20mA into the base will allow 1000mA thru the collector/emitter.
If the device you are driving has some resistance/impedance, like a motor, then that becomes the current limiting factor, and not the transistor, which is the situation you want when using a transistor as a switch.
So what I did was to connect a battery between the motor and the ground port (4x1.5V=6V) just to see if there would be more motor action. But there isnt that much change tbh. So I guess my question is, is it because Im using a 330ohm resistor for my base? does increasing the battery voltage not in anyway compensate ?
PS Ive added the new schematic, arduino board is connected to computer via usb