This Magnetic Stirrer is essentially solid state when compared to those that use a small motor and a speed reducer. Inside the beaker there is a white pill. There is a permanant magnet inside this pill. The pill gets rotated by a roatating electromagnetic field generated by a set of four coils. The coils are hooked up to a set of elctronics that essentiall thinks it is running a two phase motor. The electronics has a 555 timmer that will change the rotation from CW to CCW. The photo below shows the glass beaker with a white pill inside it. There is a metal plate with the four electromagnets under the glass beaker similar to the set on the right.