Changing the polarity of the power supply to DC motor is used to change the direction of rotation. Apart from changing the rotation direction, the H-bridge can provide additional operation modes, "brake" and "free run until frictional stop".OverviewAn H-bridge is an that switches the polarity of a voltage applied to a load. These circuits are often used in and other applications to allow DC motors to run forwards or backwards. The name is de. H-bridges are available as, or can be built from. The term H-bridge is derived from the typical graphical representation of such a circuit. An.