Bipolar stepper motor drive circuit is shown, it will use eight transistors to drive two phases. Bipolar drive circuit can drive four-wire or six-wire stepper motor, although t
he motor can only use four-wire bipolar drive circuit, it can significantly reduce the cost of high-volume applications. The number of transistors bipolar stepper motor drive circuit is twice the unipolar drive circuit, wherein the lower end of the four transistors are usually driven directly by the microcontroller, the upper transistor is a cost higher upper drive circuit. Bipolar transistor drive circuit only withstand voltage of the motor, so it is not a unipolar drive circuit as required clamping circuit.