solenoid(redirected from Solenoids)
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solenoid(sō`lənoid'), 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 electromagnetelectromagnet,
device in which magnetism is produced by an electric current. Any electric current produces a magnetic field, but the field near an ordinary straight conductor is rarely strong enough to be of practical use.
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force of attraction or repulsion between various substances, especially those made of iron and certain other metals; ultimately it is due to the motion of electric charges.
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an electrically energized coil that is usually in the form of an insulated wire wound on a cylindrical surface. If the length of the coil is substantially longer than the diameter, the magnetic field in the middle of the coil is uniform and is directed parallel to the axis of the coil. The field strength in this central part is proportional to the current and (approximately) to the number of turns. The external magnetic field of a solenoid is similar to the field of a bar magnet (see Figure 1, p. 256). When the coil has an iron core, the solenoid constitutes an electromagnet.