manually operated switch

例句：

1. 1.The manual switch is used to manually activate the alarm system.
   手动开关用于手动激活警报系统。
2. 2. The manual switch is a common feature on many old appliances.
   手动开关是许多旧电器的常见功能。
3. 3.The manual switch is easy to use and requires no electricity.
   手动开关易于使用，无需电力。