What is Solenoid?
[[File:DoorBell 002.jpg|thumb|Solenoids in door bell]] [[Image:VFPt Solenoid correct2.svg|thumb|300px|right|Magnetic field created by a solenoid]] A '''solenoid''' is a [[3-D|3 dimensional]] structure of [[wire]]. When this wire is wrapped around a [[metal]]lic block in a coil and electricity is passed through it, it has some special [[magnetism|magnetic]] properties. [[Electromagnetic induction]] makes it an [[electromagnet]] that can be switched on or off. The side in which the current appears to be passing clockwise, is the South Pole, and the side in which the current seems to be passing anticlockwise is the Northern Pole. The solenoid works just like a bar magnet, and therefore has many uses. This principle is used to create [[valve]]s, among other things. Where the solenoid operates an electric [[switch]], it is a [[relay]]. [[Pinball]] machines, [[vehicle]]s and traditional door bells use solenoids. {{Commonscat|Solenoids}} {{Tech-stub}} [[category:Electronic components]] [[category:Electromagnetism]]