What is a solenoid valve?

Solenoid valve basically works on the principle of electromagnetism. It consists of a wire coil which acts like an electromagnet. This coil controls the movement of the mechanical plunger, which ultimately controls the flow of fluid through it. Normally when current is passed through a magnetic coil, a strong electromagnetic field is created. The principle used in this valve

When the coil is energized by an external supply voltage, as it is magnetized, an electromagnetic field is created. This field attracts or repels the movement of the plunger, as it is very strong.

When energized, the plunger opens the fluid barrier and allows the fluid to escape. When the coil is de-energized, the plunger again closes the opening as the thrust is removed and blocks the passage of fluid. Thus, it can be referred to as digital output