The difference between the electronic and ordinary regulator is the fact that in electronic reg. power losses tend to be less because as we minimize the speed the electronic reg. give the power necessary for that particular speed but in case of ordinary rheostat type reg. the power wastage is same for every speed and no power is saved. In electronic regulator triac is employed for speed control. by varying the firing angle speed is controlled but in rheostatic control resistance is decreased by steps to achievespeed control.