Norsk bokmål: A diagram of the magnetic field (green) of a typical electromagnet. The drawing shows a section through the core of the electromagnet except for the windings (red), which are shown in three dimensions for clarity. The iron core of the electromagnet (C) forms a closed loop for the magnetic flux, with two air gaps (G) in it. All of the magnetic field (B) is confined to the core circuit. The blue line L is the average length of the flux path or magnetic circuit, and is used to calculate the magnetic field. This is a freehand drawing and is not quantitatively accurate as are images of magnetic field lines produced by computer. Equivalent circuit shown to the right. Drawing based on Chetvorno original work: Electromagnet with gap.svg