中文说明：
该电路由一片四双向模拟开关集成电路CD4066为核心构成。每个电路内部有四个独立的能控制数字或模拟信号传送的开关。当水箱无水时，由于180K电阻的作用，使四个开关的控制端为低电平，开关断开，LED 不发光。随着水位的增加, 由于水的导电特性，使得IC的13脚为高电平，S1接通，LED1点亮。当水位逐渐增加时，LED依次发光指示水位。水满时， LED4发光， 显示水满。同时T1导通， B发出报警声，提示水已满。不需要报警声时，断开开关K即可。
English Description：
The circuit consists of a four way analog switch integrated circuit CD4066 as the core. Each circuit has four independent switches that can control the transmission of digital or analog signals. When there is no water in the water tank, due to the action of 180K resistance, the control terminals of the four switches are at low level, the switch is disconnected and the LED does not emit light. With the increase of water level, due to the conductivity of water, pin 13 of IC is at high level, S1 is on and LED1 is on. When the water level increases gradually, the LED lights up in turn to indicate the water level. When the water is full, LED4 lights up to show that the water is full. At the same time, T1 turns on, and B sends out an alarm sound to indicate that the water is full. When the alarm sound is not required, turn off the switch K