As part of some models I'm making for a uni project (the same ones using the hard drive components for anyone who's seen my wanted thread in the sale forum), I'm using a small DC motor stripped from an old Nintendo Gamecube. I've incorporated a series of gears to step down the speed of the motor quite considerably, but I've been trying to create a simple circuit to fine-tune the final speed of the motor, and I'm a little ashamed to say, failing miserably. I'm powering the motor by a 9V battery (PP3), and so far I've tried incorporating a 10Kohm potentiometer into the circuit in an attempt to create a super simple solution, but it doesn't really work. The motor only switches on with the pot set to full, and as soon as I try to reduce the speed it just stops completely. Measuring with my voltmeter shows the voltage across the motor terminals at roughly 8.5V with the pot at full, then the voltage drops to 0.11V when I try to reduce the speed. Ideally I'd like as much control as possible, with the biggest range of speed control as possible. What's the solution? I know I'm probably missing something really obvious, but it's been a long, long time since studying anything to do with electronics. Thanks in advance for any help, much appreciated.