bobbins

A bobbin is a spindle or cylinder, with or without flanges, on which wire, yarn, thread or film is wound. Bobbins are typically found in sewing machines, cameras, and within electronic equipment. In non-electrical applications the bobbin is used for tidy storage without tangles.
In electrical applications, a coil of wire carrying a current will create a magnetic field. This effect is used in solenoids.

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