The versatile use of magnets in engineering

Magnets are used in many ways. In our everyday life we ​​use various objects that work with their help: to pay at the cash register with our bank card, for example, it is provided with a magnetic strip on which all important data is stored. Even our smartphone, with which we call every day, would not work without china magnet. Useful little helpers are also refrigerator magnets that we use to regularly attach important notes. 
Many commonly used items work only through the use of magnetized metals or electromagnetism. Especially from the technology magnets are indispensable:

  • Compass: A compass consists of a transparent housing in which there is a smoothly mounted and freely movable magnetic needle. This aligns with the field lines of the Earth’s magnetic field. It is possible to adjust in north-south direction, since the position of the magnetic poles deviates only minimally from those of the geographic poles.
  • Electric bell: A bell consists among other things of an iron coil, which is usually wound horseshoe-shaped. Closing the DC circuit by pressing the bell button can generate a periodic acoustic signal.
  • Speaker: An important component of loudspeakers is an electromagnet. Their operating principle is based on the magnetic effect of a current-carrying, movable coil, which protrudes into the permanent magnet. If they are traversed by different levels of electrical currents, the current fluctuations are converted into acoustic signals.
  • Lifting magnets: Lifting magnets serve to lift heavy, ferromagnetic objects. Turning on the power supply, a strong magnetic field builds up around its coil, attracting metallic objects. That is why they are usually used to transport scrap metal to rubbish dumps to lift enormous quantities of metal.

    A trial team uses a magnet made of neodymium, which has an adhesive force of 200 kilograms. Glass, porcelain or bone can be crushed with the magnet of this very rare earth metal. Only through a wedge and a rubber mallet is it possible for the team from the video to separate the two magnets again. In addition, the people themselves had to wear gloves, goggles and a helmet and the surroundings with Plexiglas.