Solenoid valve is an electromechanically operated valve used to control the flow of liquids or gases. The key difference between a normally open (NO) and normally closed (NC) solenoid valve lies in their default state when no electrical power is applied.

Normally Open (NO) Solenoid Valve:

In a normally open solenoid valve, the valve remains open and allows fluid or gas to flow through the valve in its default state when no electrical power is applied. When an electric current is applied to the solenoid coil, it generates a magnetic field that pulls the valve's plunger or disc to close the valve, interrupting the flow. So, the valve is closed when it receives an electrical signal and returns to its open state when the current is interrupted or switched off.

Application: Normally open solenoid valves are commonly used in applications where it is essential to have a constant flow of fluid or gas in the default state, and the flow needs to be shut off only when the valve is energized.

Normally Closed (NC) Solenoid Valve:

In a normally closed solenoid valve, the valve remains closed and prevents the flow of fluid or gas through the valve in its default state when no electrical power is applied. When an electric current is supplied to the solenoid coil, it generates a magnetic field that attracts the valve's plunger or disc, opening the valve and allowing fluid or gas to flow. The valve returns to its closed state when the electrical signal is interrupted or turned off.

Application: Normally closed solenoid valves are commonly used in applications where it is crucial to have the flow of fluid or gas shut off by default, and the flow is allowed only when the valve is energized.