A solenoid is a coil of insulated wire wound on a rod-shaped form made of solid iron, solid steel, or powdered iron which produces magnetic field when electric current passed through it.
It is an electromechanical device. Devices of this kind can be used as electromagnets, as inductors in electronic circuits etc.
Components: Coil and movable iron core which is generally called as armature.
Working: When electric current starts flowing through the wire, it produces magnetic field inside the iron core. This magnetic field produced is depends on turns of the coil. More the number of turns of coil, more is the magnetic field produced within the wire. When the coil of the solenoid is energized with current, the core moves to increase the flux linkage by closing the air gap between the cores. The movable core is usually spring-loaded to allow the core to retract when the current is switched off.
