solenoid (sōˈlənoidˌ) [key], device made of a long wire that has been wound many times into a tightly packed coil; it has the shape of a long cylinder. If current is sent through a solenoid made of insulated wire and having a length much greater than its diameter, a uniform magnetic field will be created inside the solenoid. This field can be intensified by inserting a ferromagnetic core into the solenoid. See electromagnet; magnetism.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.