Q: what is the diff. btwn. electronic regulator and ordinary rheostat regulator for fans?

           A:The difference between the electronic and ordinary regulator is that in electronic reg. power losses are less i.e.for as we decrease the speed the electronic reg. give the power needed for that perticular speed but in case of ordinary rh type reg. the power wastage is same for every speed and no power is saved.In electronic regulator triac is employed for speed cntrl. by varying the firing angle speed is controlled but in rheostatic ctrl resistance is decreased by steps to achieve speed control.