论文部分内容阅读
1.小明在乐购超市看到:电梯上有人时运动得快,没人时运动得慢.如图是小明上网搜索到的这种电梯的部分控制电路(R是一个压敏电阻),并进行了如下分析:有人走上电梯后,压敏电阻的阻值减小,电磁铁的磁性变(填“强”或“弱”),使衔铁与触点(填“1”或“2”)接触,通过电动机的电流(填“变大”或“变小”),电动机转速变快,使电梯运动变快.解析人走上电梯后,压敏电阻的阻值减小,控制电路电流增大,电磁铁磁性增强,吸下衔铁,与触点2接触,通过电动机电流增大,电动机转速变快,电梯运动加快.
1. Xiao Ming sees in Tesco Supermarket: Some people move fast on the elevator, when nobody moves slowly, as shown in the picture below, part of the control circuit (R is a varistor) searched by Xiaoming’s Internet and carried out The following analysis: Some people walked on the elevator, the varistor resistance decreases, the electromagnet magnetism change (fill “strong” or “weak”), so that the armature and contact (fill “, Or” 2 “), the motor speed will be faster and the elevator speed will be faster through the current of the motor (fill ” bigger “or ” smaller The resistance of the sensitive resistor is reduced, the current of the control circuit is increased, the magnetism of the electromagnet is increased, the armature is sucked, and the contact 2 is contacted with the contact 2, the current of the motor increases, the speed of the motor is increased, and the movement of the elevator is accelerated.