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.

双回转机构的步进机路由TDA1521音频集成大器组成平衡桥式动路，由计算机并行口经过锁存器构成脉冲分配器。