Magnet is a kind of magnet.
Magnets can adsorb metals such as iron, nickel and cobalt, commonly known as magnets. It can be divided into ordinary permanent magnets and electromagnets that have magnetism only when energized.
If you make a magnet into a bar or needle and hang it, it will naturally point to the north and south poles of the earth. Magnets are divided into big magnets and small magnets.
Large magnet magnets are widely used. Using electromagnets, a crane for transporting steel was manufactured. When electrified, it becomes a powerful magnet, so it can absorb heavy steel.
Cut off the power supply when you put down the steel. Compared with the big magnet, the small magnet makes the compass look small and light, and its magnetism is much weaker.
The function of compass is not to absorb iron, but to reflect the magnetic force of the earth.
What is the purpose of magnets?
function
Body movements
1. North and South
2. Attracting light and small objects
3. Electromagnets can be used as electromagnetic relays.
4. Engine
5. Generator
6. Electroacoustics
7.magnetic therapy
8. Magnetic levitation
9. Nuclear Magnetic Resonance * * *
food therapy
The magnet is salty and flat; Liver and kidney meridian; quality reduction
It has the effects of calming the liver and suppressing yang, improving hearing and eyesight, calming the nerves and relieving asthma.
Indications: hyperactivity of liver yang, dizziness, palpitation and insomnia, tinnitus and deafness, asthma due to kidney deficiency.
Application in traditional industries
When talking about magnetic sources, electromagnetic induction and magnetic devices of magnetic materials, we have mentioned some practical applications of magnetic materials. In fact, magnetic materials have been widely used in all aspects of traditional industry.
For example, electrification is impossible without magnetic materials, because power generation requires generators, power transmission requires transformers, motors require motors, and telephones, radios and televisions require speakers. Magnetic steel coil structure is used in many instruments. These have been mentioned in other contents.
Properties and functions of magnets.
A mineral, magnetite; Magnets are not invented by humans, but there are natural magnetite. It should be China who first discovered and used magnets.
Therefore, the compass is one of the four great inventions of China people. As for the composition, it is iron, cobalt, nickel and so on. Its atomic structure is very special. The atom itself has a magnetic moment. Generally, these mineral molecules are arranged in disorder. When magnetic fields interact, they do not show magnetism. However, under the guidance of external force (such as magnetic field), the direction of molecular arrangement tends to be the same, which is called a magnet. Iron, cobalt and nickel are the most commonly used magnetic substances. Basically, magnets are divided into permanent magnets and soft iron permanent magnets, which combine strong magnetism to make the spin of magnetic substances and the angular momentum of electrons in a fixed direction. Soft iron combined with current (also a method to increase magnetic force) When the soft iron is removed by equal current, it will gradually lose its magnetism. As for the earliest magnet, who found that the oldest record was China Huangdi vs Chiyou's South Compass, so it was called one of the four great inventions in China! China knew about magnetic polarization in the first century BC.
During the Warring States period, a natural magnet was placed on a graduated copper plate for divination. During the Northern Song Dynasty, there were two ways to make artificial magnets. One is to place the red-hot iron needle in the north-south direction, and after rapid cooling, the iron needle is magnetized by the earth's magnetic field. The other is made by rubbing an iron needle with a magnet.
Meng Qian Bitan recorded the existence of magnetic declination, and found that under the influence of magnetic declination, the magnetic needle pointed to the south, slightly to the east than the real south. Based on this knowledge, the scientific application of magnets as compasses has been developed.
Magnet is just a general term, which refers to something with magnetism. The actual composition does not necessarily contain iron. Pure metallic iron itself has no permanent magnetism, and it will be induced to produce magnetism only when it is close to a permanent magnet. Nantian magnet is specially produced. Other impurity elements (such as carbon) are added to the general permanent magnet to stabilize the magnetism, but this will reduce the freedom of electrons and make it difficult to conduct electricity, so the light bulb will not light when the current passes.
Iron is a common magnetic element, but many other elements are more magnetic. For example, many powerful magnets are made of rubidium, iron and boron. Basic knowledge: The ancient Greeks and China discovered a naturally magnetized stone in nature and called it a "magnet". This kind of stone can magically pick up a small piece of iron and swing it at will and always point in the same direction.
Early navigators used this magnet as their earliest compass to tell directions at sea. After thousands of years of development, magnets have become a powerful material in our life today.
By synthesizing alloys of different materials, we can achieve the same effect as magnets and improve the magnetic force. /kloc-artificial magnets appeared in the 0/8th century, but the process of making stronger magnetic materials was very slow, and Al-Ni-Co was not produced until the 1920s.
Subsequently, ferrite was made in 1950s, and rare earth magnets (including NdFeB and SmCo) were made in 1970s. At this point, magnetic technology has developed rapidly, and ferromagnetic materials have also made components more miniaturized.
What is the magnetization direction? Most magnetic materials can be magnetized to saturation in the same direction, which is called "magnetization direction" (orientation direction). Non-oriented magnets (also called isotropic magnets) are much weaker than oriented magnets (also called anisotropic magnets).
What is the standard industrial definition of "North and South Pole"? The definition of "North Pole" is that after a magnet rotates at will, its North Pole points to the North Pole of the Earth. Similarly, the south pole of the magnet also points to the south pole of the earth.
How can you tell the north pole of a magnet without labeling it? Obviously, eyes alone can't tell the difference. You can use a compass to get close to the magnet, and the pointer pointing to the north pole of the earth will point to the south pole of the magnet.
How to handle and store magnets safely? Be very careful, because magnets attract each other and may pinch your fingers. When magnets attract each other, they may also be damaged by collision (knocking off corners or cracking).
Keep the magnet away from easily magnetized objects, such as floppy disks, credit cards, computer monitors, watches, mobile phones, medical devices, etc. Magnets should be kept away from pacemakers.
For larger magnets, plastic or cardboard washers should be added between each magnet to ensure that the magnets can be easily separated. Magnets should be stored in a dry and constant temperature environment as much as possible.
How to achieve magnetic isolation? Only the material that can be adsorbed on the magnet can isolate the magnetic field, and the thicker the material, the better the magnetic isolation effect. What is the strongest magnet? At present, the magnet with the highest performance is rare earth magnet, and NdFeB is the magnet with the strongest performance among rare earth magnets.
But in the environment above 200 degrees Celsius, samarium and cobalt are the strongest magnets. Types of magnets: magnets, which should be called magnetic steel, are mainly divided into two categories, one is soft magnetic and the other is hard magnetic; Soft magnetic includes silicon steel sheet and soft magnetic core; Hard magnets include Al-Ni-Co, Sm-Co, Ferrite and NdFeB, among which Sm-Co is the most expensive, Ferrite is the cheapest and NdFeB has the highest performance, but Al-Ni-Co has the most stable performance and the best temperature coefficient. Users can choose different hard magnetic products according to different needs.
How to define the performance of a magnet? There are three main performance parameters that determine the performance of the magnet: remanence Br: The permanent magnet is magnetized to technical saturation, and the retained Br is called remanence induction intensity after the external magnetic field is removed. Coercive force Hc: To reduce the B of a permanent magnet magnetized to technical saturation to zero, the required reverse magnetic field strength is called magnetic induction coercive force, which is referred to as coercive force magnetic energy product BH for short: it represents the magnetic energy density established by the magnet in the air gap space (the space between the two poles of the magnet), that is, the static magnetic energy per unit volume of the air gap.
Because this energy is equal to the product of Bm and Hm of the magnet, it is called magnetic energy product. Magnetic field: the space that produces magnetic effect on the magnetic pole is the magnetic field. Surface magnetic field: how to choose the magnet for the magnetic induction intensity at the specified position on the surface of the permanent magnet? What role should the magnet play before deciding which kind of magnet to choose? Main functions: moving objects, fixing objects or lifting objects.
Required magnet shape: disc, ring, square, tile or special shape. Required magnet dimensions: length, width, height, diameter and tolerance, etc.
Attraction of required magnets, expected price and quantity, etc.
What is the use of magnets?
Packing box, glasses case, mechanical equipment, permanent magnet sucker, magnetic twist magnetic buckle, magnetic rod, magnetic bead, engraving machine, plotter, speaker, magnetotherapy health care, luggage and leather goods, instruments, electrodeless lamp, magnetic ornaments, toys, car ceiling lamp, car antenna, car rotor, stationery, teaching instruments, bathroom, mahjong machine, furniture, door suction and magnetic EVA teaching AIDS. Compressor, automobile motor, magnetic stirrer, oil tank magnetic sealing valve, magnetic sweeper, flywheel generator, stepping motor, electronic products, permanent magnet synchronous motor, fishing gear, magnetic brush, bait tray, magnetically controlled switch, floating box, magnetic mattress, precision machinery, magnetizer, commutator, solar coater, HID hernia lamp telescopic lamp, anti-EMI magnetic filter, magnetically controlled temperature switch, magnet. Magnetic cockroach catcher, refrigeration permanent magnet filter, magnetic suspension health care bed, key adhesive magnetic control lock head, magnetic therapy health care tank, environmental protection and energy-saving magnetized nozzle, permanent magnet stop valve, ozone magnetic therapy bathtub, green magnetic wave water cup, magnetic attraction multifunctional clothes hanger, permanent magnet magnetized scale inhibitor, signal magnetic ring, brake magnetic ring, magnetic oil filter, etc.
What is the purpose of magnets? What kinds of shapes are there?
Body movements
1 refers to the north and south.
Attract light and small objects.
Electromagnets can be used as electromagnetic relays.
4. Engine
5 generator
6 electroacoustic
7 magnetotherapy
8 magnetic levitation
9 NMR * * *
food therapy
The magnet is salty and flat; Liver and kidney meridian; The quality of the town has declined;
It has the effects of calming the liver and suppressing yang, improving hearing and eyesight, calming the nerves and relieving asthma.
Indications: hyperactivity of liver yang, dizziness, palpitation and insomnia, tinnitus and deafness, asthma due to kidney deficiency.
The shape is generally horseshoe magnet and bar magnet, and there is a circle on the horn.