I removed a small DC motor from a tape deck would like to use it to drive another tape unit. The motor has a small dynamo installed on it's shaft and it generates voltage as the motor runs. Since I need to control the motor as accurately as possible I thought to build a simple circuit that uses the voltage generated by the dynamo to control the speed of the motor (=feedback). Does anyone happen to have a circuit like this? The motor runs at 1V - 3V range and the dynamo generates 0.3V when the motor runs on 1.5V for example. I don't have much more info on the motor and no marking on it either.