switchsignal

例句：

1. 1. The switch signal is used to control the flow of electricity.
   开关信号用于控制电流的流动。
2. 2. In this system, the switch signal is sent through a series of relays.
   在这个系统中，开关信号通过一系列继电器发送。
3. 3.The switch signal was used to detect when the door was closed.
   开关信号被用来检测门是否关闭。