该文件为ORCAD绘制的通用开关量板电路原理图，可以兼容N多种数字电路，采用24V直流供电，输出电流0-50mA可以驱动大部分弱点开关，接触器，继电器，指示灯，步进电机等，具有隔离抗干扰，常闭或常开可自主选择，多达12路数字量输出的优点。-The document for the general switch ORCAD drawing of the circuit board schematics, can be compatible with N variety of digital cir

基于无刷直流电机的无位置传感器控制实现，利用反电动势检测电路获取电机转子的过零点，然后延时30°进行换相(Based on Sensorless Control of brushless DC motor, the zero-crossing point of motor rotor is obtained by using back-EMF detection circuit, and then commutation is carried out with a delay of 30 deg