Special electromagnetic valve circuit board with time delay function

The utility model relates to a special electromagnetic valve circuit board with a time delay function. The circuit comprises a step-down power supply chip U1, diodes D1 to D5, resistors R1 to R9, capacitors C1 to C5, an inductor L1, an electromagnetic valve coil L2, triodes Q1 to Q3, a key S1 and a liquid level sensor switch K1, external alternating current is rectified by a diode D1 and filteredby capacitors C1 and C2; voltage reduction is carried out through the voltage reduction power supply chip U1; the working voltage of the electromagnetic valve coil is obtained; when the liquid level sensor senses that the water level in the drain valve is high; when the water level is reduced, the liquid level sensor switch K1 is switched off, the capacitor C5 continuously discharges, the energization of the electromagnetic valve coil L2 is continuously maintained, the electromagnetic valve continuously drains water, and the key S1 can realize manual water drainage, so that the waste of an airsource can be effectively