precharge pulse

例句：

1. 1. The device requires a precharge pulse to start functioning properly.
   该设备需要预充电脉冲才能正常启动。
2. 2.During the precharge phase, the battery is being charged by the charger.
   在预充电阶段，电池正在由充电器充电。
3. 3.The precharge pulse was sent out immediately after the switch was turned on.
   开关一打开，就立即发送了预充电脉冲。