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(Electrical) magnetism 1
The picture shows a simple gearbox, whose transmission ratio can easily be calculated, similar to a well-known from the automotive industry, by counting off and dividing of the respective existing magnets. It works
without contact except for the bearing of the two shafts, but can not transmit much torque. So to speak, it has a built-in overload protection.
One can imagine magnetism, for example, from the antiquity as magnetite, whose smallest units, known as dipoles, the ability had to align themselves to the earth's magnetic field. In principle, iron, cobalt and nickel
can do so, too, except that much greater forces are necessary in form of magnetic fields.
From a purely practical perspective, it is possible, a long metal rod (or screwdriver) so to magnetize by contact with a permanent magnet, in order to bring out certain small objects from otherwise inaccessible places.
There are at magnets not exactly determinable places that might be called North or South poles. Only lines of force or field lines, the quasi pass parallel spatially by magnetic body, are completely closed, and can be
visualized by a magnetic needle or iron filings. Perhaps one could denote respectively as north or south pole the greatest possible concentration preferably of equally aligned dipoles shortly near the end of a bar
magnet.
Iron, e.g., shows as long as no magnetic effect, as its dipoles are disordered. If one strikes about it with the permanent magnet, then they orientate themselves in one direction. For sheets of transformers (and ignition
coils) one uses sheets of soft iron with the ability to bring their dipoles quickly from one to the other direction and thus to strengthen particularly quickly the building of magnetic fields.
Field lines can pass through all kinds of materials, in any case air and vacuum also. Of course, the force between iron and a magnet depends on the distance. In the automotive sector one uses this fact, to determine
nondestructively and with relatively high accuracy, e.g. paint thicknesses on iron sheet.
Still remains the question of the real cause of this force, because obviously, a permanent magnet does not need to be connected to current to develop its effect. And yet the electricity plays a role in its atomic structure.
Can therefore be aligned and strenghtened a particular atomic structure as in the above-mentioned elements, one calls this element as magnetizable. An e-book needs except the backlit display, in principle also no
electricity, as long as you are reading a page. 09/15
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