Automatic water level controller

The utility model discloses a (water tower and water tank) automatic water level controller, which comprises a water pump motor D, a power supply transformer B, a relay, a semiconductor device, a resistor, a capacitor, a conducting wire, and a power supply circuit. The utility model is characterized in that the utility model is mainly composed of a switching circuit and electrodes A, B, and C in the water tower or the water tank, wherein, the switching circuit is composed of three NPN semiconductor triodes, namely, BG#-[1], BG#-[2] and BG#-[3] which are divided into two stages; a stopping-conducting-conducting-stopping switching circuit is formed; the product only adopts one relay. The automatic water level controller has the advantages of simple structure, stable operation, reliability, high safety, long service life, low price, and wide applicable range.