| By winding a coil onto a non magnetic
object such as a plastic pipe then sending an electric current through
the winding will produce a magnetic field since the coil itself has
become a magnet Fig 5A.
To increase the magnetic effect place a magnetic conductor such as an iron core inside the coil. fig 5B. By inserting the iron core into this electro magnet and then passing an electric current through the coil the iron core will be drawn into the coil as shown in fig 5C. The illustration in Fig 5 animation shows the soft iron core being drawn into the coil. The reason being magnetic force lines are elastic like those of a rubber band and will always try to become as short as possible The animation repeats to illustrate the action. In reality the solenoid tube would have a spring mounted inside operating against the action of the iron core. When the current flow is stopped the iron core would be pushed back out again. |
Fig 5 |
Fig 5 animation |