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Richard Feynman's Lectures on Physics also include a volume on electromagnetism that is available to read online for free, through the California Institute of Technology. In addition, there are popular physics textbooks that include electricity and magnetism among the material they cover, such as David Halliday and Robert Resnick 's ...
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire (likely copper) wound into a coil. A current through the wire creates a magnetic field which is concentrated along the center of the coil. The magnetic field disappears when the current is turned off.
Electromagnetic suspension (EMS) is the magnetic levitation of an object achieved by constantly altering the strength of a magnetic field produced by electromagnets using a feedback loop. In most cases the levitation effect is mostly due to permanent magnets as they have no power dissipation, with electromagnets only used to stabilise the effect.
A tape head is a type of transducer used in tape recorders to convert electrical signals to magnetic fluctuations and vice versa.They can also be used to read credit/debit/gift cards because the strip of magnetic tape on the back of a credit card stores data the same way that other magnetic tapes do.
Drawings of patent US687292, showing a first-order motor with electromagnets on one of the gears. A magnetic gear resembles the traditional mechanical gear in geometry and function, using magnets instead of teeth. As two opposing magnets approach each other, they repel; when placed on two rings, the magnets will act like teeth.
When electric currents are used to produce a magnet in this way, it is called an electromagnet. Electromagnets often use a wire curled up into solenoid around an iron core which strengthens the magnetic field produced because the iron core becomes magnetised.
The two most common forms of recording head are: Magnetic - Magnetic recording heads use the principles of electromagnetism to coerce a paramagnetic recording medium, such as iron oxides, to orient in a magnetic storage medium such as magnetic tape, floppy disk or hard disk.
series) is a product line of how-to and other reference books published by Dorling Kindersley (DK). The books in this series provide a basic understanding of a complex and popular topics. The term "idiot" is used as hyperbole, to reassure readers that the guides will be basic and comprehensible, even if the topics seem intimidating.