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.

双回转机进电机控制电路TDA1521音频集成功率大器组成平衡桥式功率驱动电路，机并行口经过锁存器成脉冲分配器。