A solenoid valve is an electromechanically operated valve used to control the flow of liquids or gases in various applications. It consists of a solenoid (a coil of wire) and a movable plunger inside the coil. When an electric current passes through the solenoid, it creates a magnetic field that moves the plunger, opening or closing the valve. Solenoid valves are commonly used in water treatment systems, HVAC systems, industrial automation, and irrigation systems. They offer precise control, fast response, and reliability, making them essential in automated fluid control processes.