皮皮学，免费搜题
登录
搜题
【简答题】
行程开关又称位置开关或限位开关, 它的作用是将 转变为电信号,使电动机运行状态发生改变,即按一定行程自动停车、反转、变速或循环。从而控制机械运动或实现安全保护。 行程开关是一种常用的小电流 电器 。利用生产机械运动部件的碰撞使其触头动作来实现接通或分断控制电路, 达到 一定的控制目的。通常,这类开关被用来限制机械运动的位置或行程,使运动机械按一定位置或行程自动停止、反向运动、 变速运动 或自动往返运动等。
手机使用
分享
复制链接
新浪微博
分享QQ
微信扫一扫
反馈参考答案：
举一反三
【单选题】I can’t finish this job by Friday. You expect too much of me.
A.
too much
B.
much too
C.
so much
D.
very much
【单选题】There is ________ work to do and the work is ________ difficult. [ ]
A.
too much, much too
B.
too much, too much
C.
much too, too much
D.
much too, much too
【单选题】Eta Carinae is hard to observe because
A.
it is too far away.
B.
there is too much dust and gas around it.
C.
the binoculars are not powerful enough.
D.
it does not send out infrared light.
【单选题】Li Lei can't go to visit the Palace Museum because he has _______ things to do. [ ]
A.
too many
B.
much too
C.
too much
D.
many too
【单选题】He eats ________ food, so he is ________ fat.
A.
much too, too much
B.
much too, too many
C.
too much, much too
D.
too much, many too
相关题目：
参考解析：
知识点：
题目纠错 0
发布
