I have scrounged 2 motors out of a printer, one ID'd as a stepper with 5 leads & works fine. I'm told the other motor, with 4 leads, is a DC Servo. Can someone recommend a way to know for sure that this is a servo and a method for lead identification. I don't quite understand the difference between these 2 motor types and when and where you would use one type Vs another. My only book on the stamp has a good section on steppers but little on servos. A·circuit diagram and elementary code for servos would be ideal. Thanks in advance for your help.