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- The transistors Q1,Q2,Q3 and Q4 form the bridge circuit. Generally these are power transistors capable of handling high current.Q5 and Q6 drive the bridge. when the 'A' is made high and 'B' low, transistor Q5 is on and it makes Q1 and Q4 on. The current flows from vcc to ground through Q1,motor and Q4.hence the motor rotates in forward direction.
- When 'A' is made low and 'B' high the transistor Q6 is on and it makes the Q3 and Q2 on.The current flow from vcc to ground through Q3,motor and Q2.hence the motor rotates in reverse direction.
- When both 'A' and 'B' are low all the transistors are cutoff.
- Making both 'A and 'B' high simultaneously should be avoided.
