Thousands of products in stock
Electromagnetism
The definition of electromagnetism is simple: when current flows through a conductor, a magnetic field forms around it. In this case one speaks of electromagnetism. The electromagnetic interaction is one of the fundamental forces of physics and has been intensively researched since its discovery by the physicist Oersted and later Michael Faraday and James Clerk Maxwell (19th century: Maxwell equations). Using practical phenomena such as light, electricity and magnetism, the application of electromagnetism in everyday life can be recognized and understood.
What are electromagnetic fields?
Moving electrical charges are always surrounded by magnetic fields. The lines of this electromagnetic field are like circles around the conductor and are determined by the current direction. If this changes, the magnetic field also re-aligns.
How does an electromagnetic field develop and how can it be determined?
To determine the direction of the magnetic field lines, one can imagine grasping the conductor with the right hand and pointing the thumb in the current direction. The remaining fingers surrounding the ladder provide information about the direction of the field lines (corkscrew rule or right-hand rule).
If the conductor is now wound into a coil, similar magnetic forces arise as with a bar magnet. At one end of the coil, the magnetic field lines exit and on the other again, which is like the effect of a magnetic pole. The more turns the coil has and the higher the current, the stronger the magnetic field.
How can electromagnets be built?
If a ferromagnetic material (for example a soft iron core) is placed inside the coil, the resulting magnetizing forces can be used as an electromagnet. When the current is flowing, all magnetic elemental districts are aligned in the direction of the electromagnetic field. As a result, the force inside the coil is highest and decreases toward the outside. Electromagnets therefore have a great effect only near their core. When the power is turned off, the magnet loses most of its power.
Electromagnetism has the highest relevance not only in physics or electronics - there are also various applications in industry. For example, as lifting magnets for cranes, as excitation field generation in electric motors or as magnetic rail brakes for rail vehicles.