There are many type of motors used for various applications today. In general they can be divided into two classes: self commutated motors and externally commutated motors. Universal motors and brushed DC motors are the only truly self commutating motors although an induction motor that is connected directly to the mains, single or three phase, requires no commutation to run at constant speed. Motors like steppers, Brushless DC (BLDC), switched reluctance and induction motors driven by variable frequency drives all require external electronics to provide the commutation for the motor. Of these motors, steppers are probably the easiest to drive and that makes them attractive for low cost small power applications.