PWM with TIP120 driver makes motor beep

dc42 - You mentioned "logic level gate drive" as a requisite for a transistor driven directly by the Arduino. Is the reason for this that the output of the Arduino is very low amperage? Also, logic level, to me, means on or off - is this thinking correct? What other type(s) of gate drive might there be? Just trying to get my head around some of the terms. Thanks.