To control stepping motors, the balance bridge power drive circuit is made up by TDA1521 integrated audio power amplifier, the pulse allotter is made up by the parallel ports of computer and latches.

双回转构的步进制路由TDA1521音频集成功率大器组成平衡桥式功率路，由计算并行口经过锁存器构成脉冲分配器。