Subsection 4.4.8 Solenoids
A solenoid is an electromechanical device that consists of a coil of wire wound around a cylindrical core. When electric current passes through the wire coil, it generates a magnetic field around the coil. This controllable magnetic field is used to produce various effects.
Solenoids are used in various applications, such as in relays, solenoid valves, actuators, etc. Solenoid operated device contain an armature, which is a movable part placed near the solenoid coil that responds to the magnetic field generated by the current flowing through the coil and produces mechanical motion.
For example, electromagnetic relays control the switching of electric circuits. When the solenoid coil is energized, it generates a magnetic field that can either attract or repel the movable armature to open or close a contact. When the coil is de-energized a spring restores the contact to its normal position.