220V AC passes through the A-B end of power switch s1-1, enters the electronic step-down device and drops to 10v-12v low-voltage AC. the rectifier filter circuit composed of vd1-vd4 and C1 is transformed into smooth DC, and then stabilized to 7V through LM317. After entering the brightness regulating switch S2 through the A-B end of power switch S1-2, it is used for high brightness LED 1-lde8. Electronic voltage reducers can be purchased on the market, and small ones should be selected. In order to make the power switch S1 serve as the AC / DC conversion switch, two groups of 3-position small toggle switches or rocker switches should be selected. When the A-B end of s1-1 is connected, the AC power is supplied. When the B-C end of S1-2 is connected, the DC power is supplied to the internal pool. When the toggle piece of S1 is moved to B, the circuit is disconnected, and the night light is off. In order to make the LED work within the normal range of 3.5V, the vd10 connected to the positive pole of the battery reduces the voltage of 7.5V to 6.9v.