Universal motors may be used with AC or with DC supply current. The advantages of universal motors are the high starting torque, a very compact design and the high speed. Simple control with an AC supply can be implemented using a low end microcontroller and a single Triac or an ACS. Improved performance can be achieved using a DC chopper drive that rectifies the AC current and uses a Power MOS to provide a PWM drive to the motor. The most of the universal motors are unidirectional. Bidirectional motors using two coils on the stator can be driven energizing only one of them for the respective direction.