Solenoids and electromagnets technically are not the same thing, but people talk as if they are. A solenoid is just a coil of wire, but when you run a current through it, you create an electromagnet. Since this is by far the most useful application of a coil of wire, it’s not surprising that when you say the word ‘solenoid,’ people tend to assume you mean electromagnet. Electromagnets are particularly useful because, unlike regular magnets, they can be switched on and off, and strengthened by increasing the current flowing through them. It also refers to any device that converts electrical energy to mechanical energy using a solenoid. The device creates a magnetic field from an electric current and uses the magnetic field to create linear motion.

In other words:

When a lazy charge sits on its couch, doing nothing, it is surrounded by an electric field. This makes sense, because it’s an electric charge, after all. But once that charge gets some motivation and goes for a run around the block, suddenly it produces a magnetic field. This might strike you as odd, and you wouldn’t be alone! As physicists figured out later, both fields are part of the same force of nature: electromagnetism. Because of this, we can create a magnet by simply running a current through a wire. When we run a current through a solenoid, however, we get a super-strong magnet because the magnetic field is concentrated inside the coil. This can be incredibly useful in our everyday lives.

Normally Closed Solenoid

Solenoid valves help to control the flow of liquids … When a normally closed solenoid valve is not powered, the plunger is down, effectively sealing the valve and preventing the flow of liquids. Once the normally closed solenoid valve is powered or energized, the magnetic field causes the plunger to rise.

Solenoids offer fast and safe switching, high reliability, long service life, good medium compatibility of the materials used, low control power, and compact design.