The two-position three-way solenoid valve has three vents in two positions, one of which is the air inlet (P) and the other two are the air outlet (A / B). When the solenoid valve is electrically excited, P and A are When the power is lost, the two fingers of the P and B ports have two positions. The tee is three ports, one air inlet, P port, or one port, one working port, two ports, one exhaust port, and three ports. . Divided into normally open and normally closed. The working principle of normally open is that after the power is turned on, the valve core moves to open the gas circuit. After the power is turned off, the valve core is reset and the gas circuit is closed.