Design on a unipolar and unidirectional stepper motor circuit

A unidirectional and unipolar stepper motor driver has been designed, for the purpose of effectively solving many existed pressing problems in the stepper motor such as high costs, poor universality, complex circuitry, and inconvenient manipulation and so forth. The unidirectional and unipolar stepper motor will become outstanding as the result of its low costs, stable performance, suitable for computer control and could be driven by unipolar stepper motor. The circuit employs CD4017 to distribute pulse, and applies 74LS02 TTL to converse the single-pass four circulations into dual-pass four circulations, and utilizes the integrated Darlington pairs (Darlington transistors) to amplify the power, and then activates the stepper motor by the amplified power. It has been verified in the experiment that the circuit operates stably and pertains high control accuracy.