Dual H-Bridge
The Motor Driver Module is an L298N Dual H-Bridge. The H-Bridge is the common circuit design for controlling current flow and direction in motor coils.
The H-Bridge is named for its structure: two transistors (or switches of some kind) in series form the left- and right- side vertical strokes of the H, with the load bridging the junctions between each side. Opening or closing appropriate pairs of switches on the opposite sides of the load allow reversal of its current flow. The simulation video shows a basic H-Bridge in operation; the control signals in blue and green open and close the required transistors on opposite sides of the load, with the resultant current flow and load voltage shown in yellow.
Note that if both controls are active, this simplified H-Bridge will bypass the load and short out the power supply … definitely a fault condition. Most H-Bridge circuits available in integrated circuit form (including the L298N) add additional circuitry to prevent this from happening, and provide Enable and Direction inputs for the motor controls.
The Dual H-Bridge packages identical circuits for independent control of two motor coils: either two motors operating independently, or the two coils in a single stepper motor.
