An H-bridge circuit uses switches to control current direction. Complete with 1 = , 0 = GND.
One direction of current flow (“forward”) would be:
The reverse would be:
Expressed as a logic table, we would have:
Other cases:
- To have the motor “coast”, such that no power is applied, we would shut off all 4
- To brake the motor, we ground both sides by turning N1 and N2 on but keeping the PMOSes off
- To short circuit, we run the circuit through one side without going through the motor.
On many circuits, an LED is added to see which way current is flowing:
