A solenoid (from the French solenoid, derived in turn from the Greek solen "tube, channel" + combined form of Greek eidos "form, form") is a coil wound on a strongly packed propeller. The term was invented by the French physicist André-Marie Ampère to designate a coil helicoidal.
In physics, the term refers to a coil whose length is substantially greater than its diameter, often wrapped around a metal core, which produces a uniform magnetic field in a volume of space (where some experiment may be carried out) when An electric current is passed through it. A solenoid is a type of electromagnet when the purpose is to generate a controlled magnetic field. If the purpose of the solenoid is rather than impeding changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet. Not all electromagnets and inductors are solenoids; For example, the first electromagnet, invented in 1824, had a horseshoe shape instead of a cylindrical solenoid.
In engineering, the term can also refer to a variety of transducer devices that convert energy into linear motion. The term is also often used to refer to a solenoid valve, which is an integrated device containing an electromechanical solenoid that drives a pneumatic or hydraulic valve or a solenoid switch, which is a specific type of relay that internally uses an electromechanical solenoid To Operate an electrical switch; For example, an automotive starter solenoid, or a linear solenoid, which is an electromechanical solenoid. There are also solenoid bolts, a type of electronic-mechanical locking mechanism.
It can be understood in the following video: