Lab 6B: H-Bridge


For this lab, I learned how to control a DC motor’s direction using an H-bridge.

To reverse a DC motor, you need to be able to reverse the direction of the current in the motor. The easiest way to do this is using an H-bridge.


For this lab, I used almost the same circuit as in Lab 6A: Motor Control. I removed the transistor and LED and added an H-bridge and a switch.

An H-bridge is an electronic circuit that enables a voltage to be applied across a load in either direction. Here are the two basic states of an H-bridge:

The H-bridge is used to reverse the polarity of the motor.

The following is the pin logic for the H-bridge:

Many of the pins are not used for this lab as this H-bridge can be connected to two DC motors.

Here is the H-bridge in action:

Notice how I can increase the voltage of the external power supply. The switch is used to change the state of the H-bridge (resulting in the reversed polarity of the DC motor).

The code used to program the microcontroller can be found here.


Overall, this lab was a great way for me to learn how to control a DC motor’s direction using an H-bridge. This was my first experience connecting an H-bridge to a circuit. I enjoyed this lab and hope to use an H-bridge creatively in the near future.

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