Introduction To Magnetism & Inductance

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Introduction to Magnetism & Inductance Magnetism When elemental atomic particles move in certain materials such as iron, nickel or cobalt a magnetic field is generated. Materials that possess this property are known as ferrous or ferromagnetic materials. All ferrous materials will also react to an external magnetic field, such as a magnet or electromagnet. As a ferrous material is exposed to a magnetic field its atoms will align effectively creating many tiny magnets with north and south poles. The above diagram shows to samples of a ferrous material. Fig A shows the atomic arrangement of the material without the influence of a magnetic field. Fig B shows how the atomic arrangement changes when an external magnetic field is applied from a permanent or electro magnet. The fig illustrates that the material now possesses a North (left) and South (right) end poles While a magnetic force is applied to the ferrous material it will act as a magnet itself. The Fig to the left shows the ferrous material exerting a magnetic influence. This influence is represented with lines of magnetic flux shown arrowed from N to S poles. A free North pole will always move in the direction of these arrows to find the closest / strongest magnetic south pole. There are many different ferrous materials that all possess different magnetic properties. These vary from field strength to inductance time (the time it takes for the atomic particles to arrange). While some materials lose their own field as soon as a outside field is removed others retain their field and become magnetic for longer time periods Electromagnetism When an electrical current flows along any conducting material a magnetic field forms around it in a series of concentric circles as shown below: Fig: shows the magnetic field setup around a conducting material. The same field is present along the
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