Motor drivers produce a large amount of heat and thus are very inefficient.. Also, they are expensive too..
In this circuit, 2 relays are used to control the direction of motor.. This circuit is very efficient since no heat is produced and thus energy is not wasted.. The circuit consist of simple relays which can be easily controlled by a microcontroller and is very cost effective..
However, one downside of this circuit is that speed control is NOT possible using just relays.. For speed control we have to use mosfets!
